Good night, Iowa.

DES MOINES — The weekend is over. The senators on the campaign trail are turning into pumpkins, as Amy Klobuchar put it. And we’re signing off for the night.

If you’re just catching up, you can read an overview of the day here.

Our team of reporters in Iowa will update you throughout the week as Joe Biden and Pete Buttigieg campaign uninterrupted and the senators’ surrogates try to keep the energy up for them on the ground.

And, unlikely though it may sound, things are happening outside of Iowa too. Ashley Judd is campaigning for Elizabeth Warren in New Hampshire, for instance. And don’t miss our “20 Questions” series with the presidential candidates.

DES MOINES — News that President Trump told John Bolton, the former national security adviser, that he wanted to continue freezing aid to Ukraine until officials there helped with investigations into Democrats including the Biden family rippled through the campaign trail in Iowa on Sunday night.

Senator Amy Klobuchar, who is taking a 6 a.m. flight back to Washington on Monday morning for the impeachment trial of Mr. Trump, said that the news, which was based on an unpublished manuscript of Mr. Bolton’s book, meant Republicans would have to allow for the Senate to hear from more witnesses, including Mr. Bolton.

“I don’t know how my Republican colleagues cannot call for witnesses,” she said at her final event of the day here in front of a standing room-only hall. “Senator Romney has called for witnesses, they should all be calling for witnesses.”

Speaking at a live town hall here broadcast by Fox News, Pete Buttigieg, the former mayor of South Bend, Ind., echoed Ms. Klobuchar’s calls for the Senate to hear more.

“Just now, we’re getting more indications about John Bolton, and what he knew, which is one more reason why, if this is a serious trial, we’re going to have the witnesses and evidence,” Mr. Buttigieg said.

After an event in Marshalltown, Mr. Biden spoke briefly to reporters about Mr. Bolton’s account. “I’ve not seen the manuscript,” Mr. Biden said. “I don’t have any idea what’s in the book. But if it in fact contradicts Trump, it’s not a surprise.”

Nick Corasaniti reported from Des Moines, and Thomas Kaplan from Marshalltown, Iowa.

Credit…Jordan Gale for The New York Times

MARSHALLTOWN, Iowa — One of former Vice President Joseph R. Biden Jr.’s go-to arguments on the campaign trail is to stress the need to choose a Democratic presidential nominee who will help candidates down the ballot.

Ahead of the Iowa caucuses, he is deploying some of those down-ballot candidates to vouch for him.

At an event with Mr. Biden in Marshalltown on Sunday, Iowans heard from three freshman House members: Representatives Abby Finkenauer of Iowa, Colin Allred of Texas and Chrissy Houlahan of Pennsylvania.

In an effort to appeal to Iowans, Mr. Allred contended that Mr. Biden would have broader appeal in Texas than his Democratic rivals.

“I need you to give us, in Texas, Joe Biden,” he said. “What do I mean by that? Joe Biden puts Texas in play. He absolutely puts Texas in play.”

Mr. Allred told the crowd that there were people in his community “who are looking for another option.”

“Joe Biden,” he said, “is the only person running for president who will get their vote.”

WEST DES MOINES — What’s it like to be a still-undecided Iowa Democrat eight days before the state’s first-in-the-nation presidential caucuses?

Ann Clary, a state budget analyst, and Holly Brink, a financial analyst, drove from Waukee to see Pete Buttigieg in West Des Moines Sunday to see if they should support him over the other candidates they are still considering.

Ms. Brink, 54, also likes Senator Amy Klobuchar of Minnesota and Ms. Clary, 55, is considering Ms. Klobuchar and former Vice President Joseph R. Biden Jr.

“I’m really up in the air,” said Ms. Clary. “I like what they are saying, but it’s hard to tell, they are all so similar.”

Ms. Brink said she was most concerned with which candidate had the best chance to defeat President Trump in November, yet she conceded she had no idea how to tell who that would be.

Ms. Clary said the decision has cost her sleep.

“Sometimes I can’t fall asleep at night,” she said. “I just can’t stop thinking about it.”

Both said they would eventually back whomever Democrats nominate, though they might not be thrilled about some options.

“I might have to hold my nose” for Senator Bernie Sanders of Vermont, Ms. Clary said.

“I had to do that last election,” Ms. Brink said. “I was not a Hillary fan.”

Representative Ayanna S. Pressley of Massachusetts, a co-chair for Senator Elizabeth Warren’s campaign, stumped on her behalf at events in South Carolina this weekend. She said in a phone interview on Sunday that she was not worried about recent poll numbers that showed Ms. Warren was gaining little new support from black voters.

“The more people hear her message, the more people she converts,” Ms. Pressley said.

“I don’t put much stock in the polls,” she said. “There’s a shift occurring, and you can’t poll transformation.”

A recent poll from ABC/The Washington Post showed Ms. Warren had 9 percent support among black Democrats. Former Vice President Joseph R. Biden Jr. led the entire field with 51 percent support, and Senator Bernie Sanders of Vermont was the only other candidate in double digits, with 15 percent.

Ms. Warren has gained the support of numerous black activists, and she has sought to infuse her policy with special measures to correct a history of discrimination from the government. However, she and some of her rivals have been met with resistance from black Democrats wary of white politicians offering promises of big change.

Ms. Pressley said she was confident that given more time, Ms. Warren would win over black voters just as Ms. Pressley was won over herself.

“I don’t give anyone anything. Elizabeth Warren earned our endorsement,” she said. “I watched this campaign unfold, the momentum build, I listened to her vision and I read her policy.”

Credit…Saul Martinez for The New York Times

AVENTURA, Fla. — Michael R. Bloomberg on Sunday addressed rising anti-Semitism and spoke personally of his Jewish heritage in a speech at a prominent synagogue near Miami, a sign that courting Jewish voters is core to his strategy of building support in Florida.

Mr. Bloomberg, a former mayor of New York City who is running for president, is famously skipping the campaign trail in the four early nominating states, Iowa included — choosing instead to stake his presidential bid on the delegate-rich states that vote on Super Tuesday and beyond.

The speech was a rare instance of a major address by a Democratic presidential candidate this cycle that specifically confronted the rise in anti-Semitic attacks across the country. He spoke directly to Jewish Americans who may worry that progressive Democratic front-runners have too sharply criticized Israel or who may dislike some of President Trump’s agenda but support his Israel policy.

“The violence that has always threatened Israel is rearing its ugly head here in America, with alarming frequency,” Mr. Bloomberg said.

“The toxic culture the president has created is harming our relationship with Israel,” he said. “If I am elected, you will never have to choose between supporting Israel and supporting our values here at home.”

Mr. Bloomberg not-so-subtly sought to distinguish himself from Senator Bernie Sanders of Vermont, who is also Jewish and who recently took the lead in Iowa, according to a recent New York Times/Siena College poll of likely caucusgoers. Mr. Bloomberg, the billionaire former mayor of New York City, took aim not only at Mr. Sanders’s Israel policy but also at his democratic socialism.

“Now, I know I’m not the only Jewish candidate running for president,” Mr. Bloomberg said in his speech on Sunday afternoon, delivered in a ballroom with a roving blue spotlight and Israeli techno and music by the rapper Pitbull setting the mood. “But I am the only one who doesn’t want to turn America into a kibbutz.” The audience whooped.

But the speech didn’t win everyone over. Debbie Picker, who splits her time between Westchester County and Fort Lauderdale, Fla., said she was disappointed Mr. Bloomberg hadn’t taken questions on Sunday and wanted to know how he planned to elevate his profile in the race.

“We pay attention because we’re Jewish New Yorkers who were there for him for 12 years,” she said. “But if you were to go anywhere outside of the New York Metro and Miami Metro, I don’t think people know him.”

Read more here.

Credit…Tamir Kalifa for The New York Times

MARSHALLTOWN, Iowa — Former Vice President Joseph R. Biden Jr. is one of just two leading Democratic candidates who won’t soon have to return to Washington for the impeachment trial. Yet that hasn’t stopped him from enlisting enough surrogates to rival his, well, rivals.

He appeared Sunday night with a trio of freshman lawmakers who’ve endorsed his campaign: Representatives Abby Finkenauer of Iowa, Colin Allred of Texas and Chrissy Houlahan of Pennsylvania.

Also at that event, his campaign debuted its smallest — but perhaps cutest — surrogate yet: Jake Vilsack, the grandson of former Gov. Tom Vilsack of Iowa, a coveted endorser who is supporting Mr. Biden.

Calling the 10-year-old his “secret weapon,” Mr. Biden invited the elementary school student to say a few words.

“I hope that Joe Biden has good luck in this coming caucus and the rest of his campaign,” he said. “It’s going to be a long road but I think he can do it.”

Mr. Biden marveled at his ability to address a crowd, saying his childhood stutter would have prevented him from making similar remarks at Jake’s age.

“Ten years old!” Mr. Biden exclaimed. “Ten years old!”

STORM LAKE, Iowa — Even as Bernie Sanders has surged in Iowa with eight days to go, his closing argument has hardly differed from his core message: He is fighting for the working class.

But as he races around the state, he is also focusing more than ever on voter turnout: At stop after stop on Saturday and Sunday, he has made the case that he will only win here on Feb. 3 — and in the general election — if a high number of people actually vote.

“You win elections, especially against Trump, by having the largest voter turnout in the history of this country,” he said in Storm Lake on Sunday. “We are the campaign to do that.”

He went on: “I don’t care about what polls say today,” he said. “What matters is voter turnout.”

And on: “Tonight, I am asking you to do everything you can to make sure that the 2020 Iowa caucus has the larger voter turnout in the history of the Iowa caucus.”

Over the course of six stops this weekend (and with only one to go), Mr. Sanders did not take a single question from a voter.

Turning out people who do not usually participate in the political process has long been one of Mr. Sanders’ key strategies. In Iowa, he is hoping in particular to drive working class voters, Latino voters and young people to caucus sites.

Predicting caucus turnout has become something of a parlor game among Democratic officials and campaign staffers in the state — many are forecasting turnout that at least exceeds what it was in 2016.

The biggest turnout for one party’s presidential caucus was in 2008, when some 240,000 people participated in the Democratic contest that featured Barack Obama and Hillary Clinton.

Senator Michael Bennet of Colorado told New Hampshire’s WMUR television station on Sunday that he would campaign only in New Hampshire through the primary there — even on the day of the Iowa caucuses.

“The first day I came to New Hampshire, I felt a connection here, partly because Colorado and New Hampshire have very similar politics that’s basically balanced, with a third Republican, a third Democratic and a third independent,” Mr. Bennet told Jess Moran, a WMUR reporter. “And I think the agenda that I’ve developed over the last 10 years is one that is resonating with people here.”

In the four debate-qualifying polls of New Hampshire voters released this month, Mr. Bennet received 0, 0, 1 and 2 percent support. He received 0 percent support in all four comparable Iowa polls.

As one of four senators still in the presidential race, Mr. Bennet’s time on the campaign trail will be limited no matter which state he’s spending it in. Like Bernie Sanders, Elizabeth Warren and Amy Klobuchar, he will have to spend most of the coming week in Washington for President Trump’s impeachment trial.

A spokeswoman for Mr. Bennet did not immediately respond to a request for more details on his upcoming schedule.

DES MOINES — The electorate in Iowa is overwhelmingly white, but on Sunday, Joseph R. Biden Jr. fielded a question that he was eager to answer: What has he done to reach out to people of color during his presidential campaign?

Mr. Biden, whose strong support from black voters is one of his greatest political advantages in the Democratic primary race, did not hesitate.

“I was raised in the black church politically — not a joke,” Mr. Biden said, recalling his time not long after law school when he went to work as a public defender.

Mr. Biden, the former vice president, was speaking at an event in Des Moines hosted by the Des Moines branch of the N.A.A.C.P. as well as two local organizations, Creative Visions and Urban Dreams.

Mr. Biden’s strong support from black voters may not play a significant role in the Iowa caucuses, but it is of vital importance in future nominating contests, particularly in South Carolina.

“I know a lot of folks out here were wondering, why does Biden get such overwhelming support from the African-American community?” Mr. Biden said on Sunday. “Because that’s what I’m part of. That’s where my political identity comes from. And it’s the single most loyal constituency I’ve ever had.”

AMES, Iowa — It was, well, a re-endorsement, one that David Johnson, the former Iowa state senator who disavowed the Republican Party after it nominated Donald J. Trump in 2016, drove more than two hours to make.

“I was at the Iowa Farmers Union, and I heard Senator Klobuchar was going to be there,” Mr. Johnson said, recalling watching her speech one day 14 months ago and pulling her aside afterward to relay his impression.

“I’ve been with her ever since.”

Mr. Johnson had created some confusion when, on Saturday night, he introduced former Mayor Pete Buttigieg of South Bend, Ind., as the “next president,” a seeming endorsement for the 38-year-old candidate.

But Mr. Johnson said he was just being polite, and that he still backed Ms. Klobuchar.

“I live way up on the border, so she’s my neighbor,” Mr. Johnson said. “I’m just being neighborly.”

So he came far from home to introduce Ms. Klobuchar to a crowd of more than 400 packed into the back of a barbecue restaurant here on a chilly Sunday afternoon.

The senator said she was cramming in a full day of campaigning before midnight, when, she said, “I turn into a pumpkin and I go back” to Washington for the impeachment trial of President Trump.

During the event, Ms. Klobuchar also picked up the endorsement of Ross Wilburn, a member of the Iowa House and a former mayor of Iowa City. It was Ms. Klobuchar’s 17th legislative endorsement in Iowa.

She spent more than 10 minutes of her stump speech on health care, drawing an unstated contrast to candidates advocating “Medicare for all.”

“The Affordable Care Act is nearly 10 points more popular than the guy in the White House right now,” she said. “So I’m not in favor of blowing it up.”

Peppered throughout her remarks were constant reminders of her Midwest ties, and that her home state shares its southern border with Iowa.

To punctuate her pitch to lower drug prices like other countries have done, Ms. Klobuchar put her own spin on Tina Fey’s famous impression of Sarah Palin.

“In Minnesota,” she said, dryly smirking, “we can see Canada from our porch.”

Credit…Tamir Kalifa for The New York Times

In an interview this weekend, Joseph R. Biden Jr. accused Bernie Sanders of being inconsistent on Social Security, stoking fresh tension between the two leading candidates over an issue of great significance to older Iowa caucusgoers.

The two septuagenarian contenders have clashed over the subject repeatedly in recent days as Mr. Sanders seeks to make inroads into Mr. Biden’s standing with older voters. The former vice president was asked about their disagreement in an interview with New Hampshire’s WMUR News 9 that aired this weekend.

“What about those Democratic voters who say that Bernie has been consistent this whole time?” asked Adam Sexton, WMUR’s political director.

“Well, he hasn’t been,” Mr. Biden replied. “But I’m not going to attack Bernie. He has been — he hasn’t even been consistent on Social Security. But here’s the deal. I’ve laid out clearly what my plan for Social Security is. I’m going to increase Social Security benefits.”

It wasn’t immediately clear what potential inconsistencies Mr. Biden was referring to. Both men currently support strengthening the program.

Mr. Sanders has been critical of Mr. Biden’s past support for Social Security freezes and other deals that alarmed Social Security advocates at the time.

In a statement Sunday night, Mr. Sanders’s campaign manager, Faiz Shakir, ticked through Mr. Biden’s record on those measures.

“On the other hand, Bernie Sanders fought those efforts every single step of the way, and has fought his entire career to protect and expand Social Security,” Mr. Shakir said, also saying that Mr. Biden “continues trying to hide his efforts to help Republicans cut Social Security.”

Meanwhile, Mr. Biden has said the Sanders campaign is mischaracterizing part of his record on the issue.

Mr. Sanders, who has generally supported increasing funding for the program and opposed cuts, has still faced scrutiny for his use of the term “adjustments” years ago, a phrase some have taken to suggest cuts to the program, though his campaign denied that was his intent in a Bloomberg News report last week.

The Vermont senator has edged Mr. Biden in several recent early-state surveys, including in a New York Times/Siena College Iowa poll released Saturday. But that same poll found that Mr. Biden maintained a strong advantage with older likely caucusgoers.

Credit…Tamir Kalifa for The New York Times

DES MOINES — Caucuses are demanding under the best of circumstances. You have to get to a specific room at a specific time. Seats are scarce. You have to physically realign as nonviable candidates are eliminated. The process can last for hours, and you can’t leave early.

But for many Iowans with disabilities, caucusing isn’t just difficult: It’s impossible.

If a precinct is overcrowded, as many are, people in wheelchairs can’t safely navigate. If caucusgoers aren’t allowed to leave the room to use the bathroom, people with digestive diseases like Crohn’s simply can’t participate. And there is no remote participation option, which excludes people who are immunocompromised or too sick to leave their homes — people who could otherwise vote by absentee ballot in primary or general elections.

We talked to caucusgoers, advocates and the Iowa Democratic and Republican Parties about accessibility. Here’s what they told us.

Credit…Eric Thayer/Reuters

WEST DES MOINES, Iowa — Picking up on a line of attack he first introduced Saturday, former Mayor Pete Buttigieg suggested to voters here, without naming him, that it would be too risky to nominate Senator Bernie Sanders to face off against President Trump.

Mr. Buttigieg first called Mr. Sanders “a risk we can’t take” in a fund-raising appeal Saturday. During a Sunday rally at Maple Grove Elementary School here, he went after Mr. Sanders again.

“We cannot run the risk of trying to defeat this president with the same Washington political warfare mentality that brought us to this point,” he said. “It’s time for something new, it’s time for something different and it’s time to turn the page.”

Mr. Buttigieg, who is spending the final days of his Iowa campaign making a case for his own electability, suggested Mr. Sanders’s left-wing politics and pledge to organize supporters to push his agenda as president were not the prescription the nation needed.

“The country will be crying out for a president capable of unifying and healing the American people,” he said. “It won’t be enough to just say, ‘Let’s get together,’ we’re going to have to get together and do something, fast.”

When he spoke with reporters after his rally, Mr. Buttigieg drew a contrast with Mr. Sanders that alluded to Mr. Sanders’s experience in the combat of Washington politics.

“We need to turn the page on the political mind-set that got us here,” he said. “We have an opportunity to choose both unity and boldness.”

DES MOINES — It’s the final sprint in Iowa, but with three top candidates spending much of the past week in Washington as jurors for President Trump’s impeachment trial, televisions here in Iowa have been inundated with political ads to help provide air cover in this bifurcated political moment.

Over the past week, Democratic candidates have spent over $3.5 million in the four main Iowa television markets, according to Advertising Analytics, an ad tracking firm. More than $4 million is booked through caucus day, though that is likely to change as candidates make their final arguments on air.

Senator Bernie Sanders of Vermont has been rotating heavily between two ads in Iowa over the past week, one promoting his record on women’s rights, including issues like abortion access and making child care affordable, and another ad calling for a Sanders-brand of unity, asking people to “fight for someone else as much as you would fight for yourself.”

His ad focusing on women’s rights began airing after his public argument with Senator Elizabeth Warren of Massachusetts over whether Mr. Sanders once said a woman couldn’t win the presidency.

The campaign has spent more than $464,000 on ads in Iowa in the past week.

Ms. Warren also has two ads in heavy rotation, spending more than $450,000 on ads in Iowa last week.

She is evenly split between an ad showcasing her large crowds and endless selfie lines, as she repeats her campaign mantra — “big, structural change” — and an ad making the case that President Trump is most afraid of facing Ms. Warren in the general election.

Senator Amy Klobuchar of Minnesota, who is also taking part in the impeachment trial, is spending about half as much as Mr. Sanders and Ms. Warren.

Her main ad is a rehash of her 100-day plan. The ad, tapping into the candidate’s sense of humor, features Ms. Klobuchar breathlessly listing all of the policy goals she has for the first 100 days of her administration, and runs out of time before she can finish the phrase “affordable housing.”

WEST DES MOINES — Former Mayor Pete Buttigieg of South Bend, Ind., said he was “shocked” about Kobe Bryant’s death, which he learned about after a campaign event at Maple Grove Elementary School here.

“This is someone who affected so many fans and supporters,” he said. “Of course we’ll be thinking of not just his family but everyone who is going to be impacted and in mourning.”

Asked what he would remember most about Mr. Bryant, Mr. Buttigieg replied, “I mean, obviously, on the court, what he did as an extraordinary athlete.”

Then he told a story about his father. “Folks grow up looking up to our sports heroes, and you know, my father was a fan of Manchester United,” he said. “His loyalty to that team really cemented in a tragic crash that killed a number of those athletes when he was a child. It can have an effect on people for the rest of their lives when somebody that they feel a connection with, even without having met them, is lost too soon.”

In 1958, a plane carrying the Manchester United football team crashed shortly after taking off from the Munich airport. In all, 23 people died, including eight members of the team.

Elsewhere in Iowa, Senator Bernie Sanders of Vermont, responding to a question from an NBC news reporter, said of Mr. Bryant: “He’s certainly one of the great basketball players who’ve ever lived.”

DES MOINES — At former Vice President Joseph R. Biden Jr.’s second campaign stop of the day, an event hosted by the Des Moines branch of the N.A.A.C.P. and two local organizations, Creative Visions and Urban Dreams, the audience was informed that the basketball superstar Kobe Bryant had been killed in a helicopter crash, along with four other people, and a moment of silence was observed.

Mr. Biden spoke shortly thereafter and said he had learned the news as he was arriving at the event. He said he had met Mr. Bryant a couple of times. “It makes you realize that you’ve got to make every day count,” he said.

Another Democratic candidate, the entrepreneur Andrew Yang, also reacted to the news on Sunday, calling Mr. Bryant “an all-time great who had his entire life ahead of him.”

Credit…Jordan Gale for The New York Times

DAVENPORT, Iowa — Senator Elizabeth Warren was asked, yet again, the question on Sunday that has bogged down her candidacy in Iowa and elsewhere in recent months: whether a candidate from the more moderate wing of the Democratic Party would more easily defeat President Trump.

“I think the old ways of looking at things just don’t work anymore,” Ms. Warren said.

Then, as she did at last week’s debate, she invoked her own electoral history — beating a popular Republican incumbent, then-Senator Scott Brown, in 2012 — the ambitions of her agenda and her gender.

“Can we just address it right here? Women win,” she said, explaining that the “world changed” with Mr. Trump’s election and the mass protest marches led by women the day after his inauguration.

“Women candidates have been outperforming men candidates since Donald Trump was elected,” she said. “We took back the House and we took back statehouses around the nation because of women candidates and the women who get out there and do the hard work to get it done.”

She added that her focus on corruption could “pull in Republicans.”

“We’re going to win it by drawing the distinction, the sharpest distinction between the most corrupt administration in history and a Democrat who is willing to get out there and fight corruption,” she said.

PERRY, Iowa — Bernie Sanders and Joseph R. Biden Jr. are fighting over yet another issue: climate change.

After days of back-and-forth jabs over Social Security, the two leading candidates have turned to attacking each other over their plans to fight climate change.

“Well Joe, you’re wrong,” Mr. Sanders said at an event in Perry on Sunday. “Many leading scientists agree with our plan and in a few days we’re gonna have a long list of scientists who agree with our plan.”

Mr. Sanders’s remark came in response to Mr. Biden’s comment two days ago denouncing Mr. Sanders’s plan. “There’s not a single solitary scientist that thinks it can work,” Mr. Biden said on Friday.

Mr. Sanders’s sweeping plan aligns with the Green New Deal and involves reducing domestic carbon emissions by at least 71 percent by 2030.

The two men represent the two factions of the Democratic Party, and have often dealt each other glancing blows. But more recently, they have landed more direct hits over Social Security. Mr. Sanders has also gone after Mr. Biden over his vote to authorize the war in Iraq.

ANKENY, Iowa — It would have been in 1973, if Maxine Goldstein recalls correctly, and she would have been 16 or 17.

Joe Biden was a new senator reeling from the deaths of his wife and daughter. Ms. Goldstein was on Capitol Hill for a congressional workshop program, and she wanted to meet him more than anyone.

It was “his warmth, his passion, his sincerity” that drew her to him, she said. Mr. Biden spoke with her in his office for about 15 minutes — “he was remarkably generous,” she said — and someone took a photo of them.

On the back, Mr. Biden wrote:

Maxine —

Please come back and visit

Joe Biden

USS

So she did Saturday night, 47 years later, at a conference center just north of Des Moines, 350 miles from her home in St. Louis.

Ms. Goldstein, now 63, is not an Iowan. Missouri doesn’t vote until after Super Tuesday. She isn’t even positive she’s going to vote for Mr. Biden, though she is leaning that way. But she wanted to see him.

And how did it go?

“It’s everything that I imagined,” she said, her husband smiling beside her. “He’s exactly now as he was then.”

DES MOINES — If it’s Sunday, it’s shopping time at Mercado Iowa Market, a small swap meet of sorts at El Malecon Event Center in south Des Moines. The mercado features food of all sorts — carne asada tacos, cheese-oozing pupusas and tlacoyos heaped with nopales.

So just what does all that food have to do with the upcoming Iowa caucuses? The market is perhaps one of the best places to see evidence of the growing Latino community in the state, which has more than doubled in the last two decades.

That growth is likely to affect the caucus — or “el caucus,” as it is known in Spanish. More Spanish speakers than ever are expected to show up to caucus night this year. And for the first time, the state Democratic Party is offering six Spanish-language satellite caucus sites, in an attempt to increase participation.

The problem? Party officials are still scrambling to find enough bilingual Spanish speakers to work at those sites and others around the state.

Last weekend, we spent time with one interpreter as she joined a few other community activists for a local a caucus training. Vanessa Marcano-Kelly, a native of Venezuela, became a citizen just last year and will participate in her first caucus next month.

Ms. Marcano-Kelly is a precinct captain for the Sanders campaign, one of just a few designated so far for the bilingual caucus sites. But as she learned more about the process last week, she wondered just who should have her loyalty on caucus night — the campaign or individual voters? And how could anyone be sure that everything at the bilingual caucus sites would operate smoothly?

Credit…Tamir Kalifa for The New York Times

With Joe Biden still leading most national polls, his rivals, especially Bernie Sanders, are increasingly hitting out at his decades-long record.

And as Mr. Biden has defended himself, emphasizing his standing among black voters and his foreign policy experience, he has made some misleading claims.

We fact-checked some of his statements on Social Security, birth control, North Korea and his role in the civil rights movement. Read more here.

HARTSVILLE, S.C. — If you live in South Carolina, you could be forgiven for thinking that Tom Steyer is the leading Democratic challenger to President Trump.

That’s because Mr. Steyer is everywhere in the state — TV commercials, Facebook ads, old-fashioned mailers through the postal system.

A hedge-fund billionaire from California, he is using his vast wealth to lavish money on black businesses in particular, hiring dozens of African-American staff members and spending generously with black-owned news organizations.

So far, it seems to be paying off. A Fox News survey this month showed Mr. Steyer in a surprisingly strong position in South Carolina — in second place with 15 percent of the vote.

An impressive showing in the Feb. 29 primary by Mr. Steyer could chisel into support for former Vice President Joseph R. Biden Jr., who is the clear front-runner in polls here.

Mr. Steyer’s focus on courting black voters seems to have earned him some good will, or at least positive media attention.

But some experts question the wisdom of Mr. Steyer’s spending here, and whether his money could be put to better use. Nonprofit groups and community organizations always need more funding; the Democratic presidential field does not necessarily need more candidates who are unlikely to win the nomination.

“If I’m running that campaign, I’m thinking it’s great that after all these tens of millions of dollars we’re finally starting to show some movement,” said Lachlan McIntosh, a Charleston-based Democratic consultant. “But my goodness, it is worth it?”

Read more here.

Credit…Tamir Kalifa for The New York Times

DES MOINES — A new CBS News poll released Sunday shows Senator Bernie Sanders of Vermont and former Vice President Joseph R. Biden Jr. neck-and-neck in Iowa eight days before the caucuses.

The poll, which was conducted from Jan. 16-23 and has a margin of error of plus or minus 3.9 percentage points, showed Mr. Sanders with 26 percent support and Mr. Biden with 25 percent, a statistically insignificant difference. Former Mayor Pete Buttigieg of South Bend, Ind., was also very close, at 22 percent.

Senator Elizabeth Warren of Massachusetts had 15 percent support, and Senator Amy Klobuchar of Minnesota had 7 percent. Nobody else had more than 1 percent support.

Candidates must get at least 15 percent support to be considered viable in a precinct; if they are below that threshold in the first vote, their supporters must realign themselves with a viable candidate. Only those who exceed 15 percent are eligible to win delegates, some of which will be awarded at the state level and some of which will be awarded in each of Iowa’s four congressional districts.

The CBS poll paints a somewhat different picture than a New York Times/Siena College poll of likely caucusgoers released on Saturday. That poll showed essentially the same amount of support for Mr. Sanders — 25 percent — but gave him a clearer lead over his competitors, showing Mr. Buttigieg at 18 percent, Mr. Biden at 17, Ms. Warren at 15 and Ms. Klobuchar at 8. The margin of error was plus or minus 4.8 percentage points.

PERRY, Iowa — Senator Bernie Sanders opened his remarks at his first town hall meeting of the day on Sunday with a slightly wistful interlude about what could have been.

“A few weeks ago, I would not have told you that I would be spending the last week of the campaign in Washington, D.C.,” he said.

The Vermont senator planned to spend the lead-up to the Iowa caucuses much as he spent it four years ago — criss-crossing the state, greeting thousands of potential voters and holding, by his estimation, 20 or 30 events.

Instead, like the three other senators running for president, Mr. Sanders will likely spend much of the next week marooned in the Senate chamber, listening to President Trump’s lawyers make their arguments.

While this isn’t ideal, his team believes Mr. Sanders’s brand and established organization in the state will be strong enough to withstand his absence. Recent polling has buoyed their hopes: A series of state and national polls show Mr. Sanders emerging as a late-breaking leader in the contest, consolidating support from liberals and benefiting from a divided moderate wing.

Mr. Sanders said he expects the momentum to continue until the caucuses. “The reason we are going to win here in Iowa is we have the strongest grass-roots movement of any campaign,” he said.

DES MOINES — Former Vice President Joseph R. Biden Jr. has not been a favorite of newspaper editorial boards so far, and he lost out on the coveted Des Moines Register endorsement on Saturday. But his campaign emerged from the day with a different endorsement to trumpet, from The Sioux City Journal in northwest Iowa.

The Journal’s case for Mr. Biden focused on his ability to pose a strong challenge to President Trump in the general election — an argument that is central to Mr. Biden’s candidacy. The Journal suggested Mr. Biden was well positioned to attract support not only from Democrats, but also from independents and from “disgruntled Republicans.”

“We view Biden as a pragmatist — and we believe his pragmatism is an attribute,” the newspaper wrote in its endorsement. “We refuse to believe middle-of-the-road compromise should be or is a relic of the past.”

Northwest Iowa is a heavily Republican area, and it has not been a top focus of campaigning for Democratic presidential candidates. But The Journal’s track record bodes well for Mr. Biden. The newspaper endorsed Al Gore in the 2000 primary race and Barack Obama in the 2008 contest, both of whom went on to win the Iowa caucuses and become the Democratic nominee.

Credit…Jordan Gale for The New York Times

DAVENPORT, Iowa — Patrick Peacock, an alderman on the Davenport city council, said before a gymnasium filled with more than 300 people Sunday morning that he had the high honor of introducing the next president of the United States: Senator Elizabeth Warren.

Then he tried to get the crowd fired up.

“El-Liz-A-Beth! El-Liz-A-Beth! El-Liz-A-Beth! El-Liz-A-Beth!” he exhorted.

The crowd tried. But four syllables do not an easy chant make — a fact that Ms. Warren acknowledged when she jogged out to the familiar tunes of Dolly Parton’s “9 to 5.”

“Next time, I’m going to get a more chantable name,” Ms. Warren joked.

Luckily, she has some ready-made options: Ms. Warren was known as Betsy growing up and later as Liz.

The first time we interviewed the Democratic presidential candidates, late last spring, we had a pile of yes-or-no, either-or policy questions to ask, many of them representing litmus-test issues at the heart of Democratic politics: single-payer health care and foreign wars, wealth concentration and tech regulation.

Our second round of interviews was different. For starters, we asked fewer candidates to participate, inviting only the ones with a realistic shot at accumulating a substantial number of delegates.

And we asked them, for the most part, a different genre of questions, exploring not just policy issues but also their ideas about leadership and the presidency.

Our hope was to produce a set of interviews that would guide voters trying to make a difficult final decision about which candidate they’d like to put in the country’s most powerful job.

Take a look.

Credit…Jim Wilson/The New York Times

DES MOINES — The entrepreneur Andrew Yang qualified for the next Democratic debate with a string of four strong polls released in quick succession on Saturday and Sunday.

Two polls of New Hampshire voters — one from CNN and the University of New Hampshire, and the other from NBC News and Marist — showed Mr. Yang at 5 percent, the minimum to qualify for the debate.

A national Fox News poll also showed him at 5 percent. And a national ABC News/Washington Post poll released Saturday found him at 7 percent, his best showing ever in a debate-qualifying survey.

Mr. Yang, who did not qualify for the last debate, is the seventh candidate to qualify for the next one. He had long since met the Democratic National Committee’s other qualification requirement: a minimum of 225,000 donors.

“America has spoken,” Mr. Yang’s campaign chief, Nick Ryan, said in a statement Sunday morning. “Voters clearly missed Andrew Yang’s presence in the most recent debate, and now they are making sure he will be on the debate stage in New Hampshire. The race for the nomination has only just begun, and Andrew Yang is going to keep fighting for all Americans to have their voices heard.”

Mr. Yang will join former Vice President Joseph R. Biden Jr.; former Mayor Pete Buttigieg of South Bend, Ind.; Senators Amy Klobuchar of Minnesota, Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts; and the former hedge fund executive Tom Steyer onstage in Manchester, N.H., on Feb. 7, four days before the New Hampshire primary.

STORM LAKE, Iowa — Pete Buttigieg had one of northwest Iowa’s most coveted surrogates introduce him before a town-hall-style event Saturday night at Buena Vista University: David Johnson, a former state senator who in 2016 quit the Republican Party when Donald J. Trump won its presidential nomination.

Mr. Johnson, who didn’t seek re-election in 2018, represents exactly what Mr. Buttigieg says he’d bring as the Democratic presidential nominee: support from former Republicans disgusted with Mr. Trump.

The only problem? Mr. Johnson endorsed Senator Amy Klobuchar of Minnesota in September. He’s planning to serve as a precinct captain for Ms. Klobuchar in his hometown, Ocheyedan, just over the border between Iowa and Minnesota.

That didn’t stop the Buttigieg campaign from informing reporters that Mr. Johnson, who introduced Mr. Buttigieg as “the next president of the United States,” had “announced his support for him.”

Mr. Johnson said after the event that he’s still backing Ms. Klobuchar.

“They’re two good candidates,” he said. “I’m just happy with someone from the Midwest.”

Mr. Johnson said he was asked to introduce Mr. Buttigieg after the scheduled introducer had car trouble and missed the event. He called Mr. Buttigieg the next president, he said, because that’s just something you say when someone visits Iowa.

“It’s a courtesy,” he said. “I would do it for anyone who had a D behind their name.”

Despite his affection for them, Mr. Johnson doesn’t expect either Mr. Buttigieg or Ms. Klobuchar to win the state’s caucuses.

“My prediction is Senator Sanders,” he said, referring to Senator Bernie Sanders of Vermont, who is leading in the latest Iowa polling.

“There’s a lot of things that have happened, and Secretary Clinton didn’t do any good to tamp down his case,” he said, referencing critical remarks Hillary Clinton made last week about her former primary rival.

“I tell you, that guy’s people are going to be out there with a vengeance.”

AMES, Iowa — The impeachment trial scrambled plans for the senators competing in the Democratic primary race. They would normally be blitzing Iowa in the final days before the caucuses, but they instead spent much of the past week in Washington, serving as jurors for the trial of President Trump, before returning to Iowa on Saturday.

Bernie Sanders took something of a lighthearted tone about his Washington detention.

“I am really delighted to be here tonight,” he told a crowd in Ames, after being introduced by the filmmaker Michael Moore and Representative Alexandria Ocasio-Cortez of New York. “You don’t know how delighted I am, because last night, I didn’t know that I would be here!”

Earlier in the night, he also briefly touched on his time in Washington.

“As you well know, we have had to radically change our schedule in the last week — kind of toss it into the garbage can and begin anew,” he said at a stop on Marshalltown. “But we are going to be back here in Iowa in the next week every moment that we possibly can.”

It is not clear how much, or even if, being away from the trail will affect Mr. Sanders and the other senators in the race. For now, he is surging in Iowa, and gaining momentum in other early states.

A New York Times/Siena College poll released on Saturday showed Mr. Sanders in a commanding first place, with 25 percent support — 7 percent ahead of his nearest opponent. A poll on Sunday from CNN showed him leading in New Hampshire, too.

MUSCATINE, Iowa — The Des Moines Register endorsed Senator Elizabeth Warren for the Democratic presidential nomination on Saturday night, calling her “the best leader for these times.”

The newspaper, Iowa’s largest and most influential, gave Ms. Warren a boost just over a week before the caucuses on Feb. 3, when Iowans will take part in the first nominating contest of the primary cycle.

The Register’s endorsement landed as Ms. Warren worked her way through her selfie line after a town-hall-style event in Muscatine, Iowa.

She did not find out until after she took the final picture, when her communications director, Kristen Orthman, pulled her aside to share the news.

Ms. Warren leapt back in excitement — pulling her hands to her chest, as if to say, “what, me?” — and then pumped both hands in the air and did a little dance. Ms. Orthman then appeared to show Ms. Warren the editorial on her phone.

Ms. Warren gulped down a sip of coconut water, one of her campaign trail staples, and headed over to a gathered group of reporters and microphones with a smile.

“I just heard and I’m delighted,” Ms. Warren said of the endorsement. “It really means a lot to me. I’m very happy.”

The endorsement was one of three released in quick succession Saturday evening. The New Hampshire Union Leader backed Amy Klobuchar, writing: “Her work in Washington has led to the passage of an impressive number of substantive bills, even as the partisan divide has deepened.

And The Sioux City Journal in Iowa gave its support to Joseph R. Biden Jr., calling him “the candidate best positioned to give Americans a competitive head-to-head matchup with President Trump.”

DES MOINES — We’re approaching the final week before the Iowa presidential caucuses, and the Democratic campaign pulsed with a newly urgent and frenetic energy on Sunday morning as the five top candidates descended on the state and a crush of new polls and endorsements came out.

Here’s how to think about it:

There are eight days left until the caucuses next Monday night, and there are plenty of undecided or wavering Iowa voters who have a history of breaking late in favor of a candidate. Senator Bernie Sanders of Vermont is ahead in Iowa in the latest New York Times/Siena College poll, while he and former Vice President Joseph R. Biden Jr. are effectively tied in a new CBS News poll in Iowa published on Sunday. Senator Elizabeth Warren of Massachusetts just won The Des Moines Register’s endorsement and Mr. Biden picked up the Sioux City Journal’s backing.

Most of the campaign events on Sunday are in the Democratic population centers of Des Moines, Cedar Rapids and Davenport, and the candidates are making a case for their policy ideas but also for their electability.

While Mr. Sanders almost tied Hillary Clinton in Iowa in 2016, the competition is much greater now, but also fluid. There are two liberal candidates — Mr. Sanders and Ms. Warren — competing for Iowa’s big progressive vote, which often turns out energetically on caucus night. Three moderates — Mr. Biden, former Mayor Pete Buttigieg of South Bend, Ind., and Senator Amy Klobuchar of Minnesota — are largely carving up the centrist vote.

Yes, there is overlap among the candidates. Ms. Warren and Mr. Buttigieg are both chasing upper-income, college-educated, left-leaning Democrats, for instance. But polls indicate that Mr. Sanders could be on a path to putting together a plurality of caucusgoers next Monday night.

The main takeaway from the new polls — in addition to the Iowa polls, there were two national surveys and two New Hampshire primary polls — is that Mr. Sanders and Mr. Biden are now co-front-runners, with Mr. Biden having the edge nationally and Mr. Sanders in New Hampshire (as well as Iowa). Mr. Buttigieg and Ms. Warren have strength in New Hampshire as well, but their fate in the Feb. 11 primary there is partly dependent on how well they do in Iowa.

We are out with the top five candidates across Iowa today and will bring you updates throughout the afternoon and evening.

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