How We Got to Super Tuesday: 6 Campaigns in Photos

After a month focused on caucuses, primaries and debates in four states, the Democratic campaign is moving on. Super Tuesday, when 15 states and territories vote, presents a whole new map that could shake up the narrative of the race.

Senator Bernie Sanders is currently leading in the delegate count and in the polls, but former Vice President Joseph R. Biden Jr. can claim the most recent primary win. Senator Elizabeth Warren is pushing ahead despite recent defeats. Pete Buttigieg and Senator Amy Klobuchar ended their campaigns and Michael R. Bloomberg has yet to appear on a ballot.

New York Times photographers have followed the candidates every step of the way. Here is what they saw over the last month.

Senator Bernie Sanders of Vermont started the primary season with a boom. He won the popular vote in Iowa and claimed a narrow victory in the New Hampshire primary.

Going west, Mr. Sanders looked to solidify his front-runner status in Nevada by tapping into the Latino vote. It worked. By the time he was declared a winner there, he was already at his second rally in Texas, drumming up support in one of the most delegate-rich states voting on Super Tuesday.

Mr. Sanders is the first presidential candidate to win Iowa, New Hampshire and Nevada. He came in a distant second in South Carolina, but that was expected. His goal moving into Super Tuesday is to amass an unstoppable delegate lead by capturing large states like California.

In his third run for the White House, former Vice President Joseph R. Biden Jr. had a rough start. He placed fourth in Iowa and fifth in New Hampshire. But he urged supporters to stick with him until more diverse states could have a say.

Patience paid off. Mr. Biden regained strength in Nevada, finishing in second place. In South Carolina, his relationships with former President Barack Obama and Representative James E. Clyburn, the highest-ranking black member of Congress and a kingmaker in the state’s primary, endeared him to black voters. He won with nearly 50 percent of the vote.

With the win in South Carolina coming just three days before Super Tuesday, Mr. Biden’s momentum could help him in states like Texas, North Carolina and Virginia, where there are more moderate Democrats.

Pete Buttigieg, the 38-year-old former mayor of South Bend, Ind., focused nearly all his resources on Iowa. His visits to rural parts of the state paid off when results showed him nudging ahead of Senator Bernie Sanders in the delegate totals, even though he lagged in the popular vote.

Mr. Buttigieg sought to maintain the momentum from Iowa during a week of campaigning in New Hampshire. On election night, he finished in second place, just under 4,000 votes behind Mr. Sanders.

Senator Elizabeth Warren of Massachusetts rose to the top of the field in 2019, but faltered as voting began. She came in third in Iowa, but the bigger blow came with a fourth-place finish in New Hampshire.

After those back-to-back disappointments, Ms. Warren needed to reinvigorate her campaign. That moment arrived with a breakout performance in the Nevada debate. Within the first five minutes, Ms. Warren went through a checklist of attacks on rivals, with many directed at Michael R. Bloomberg. Her campaign raised $2.8 million after the debate, but she notched another fourth-place finish in Nevada’s caucuses.

Ms. Warren is pushing beyond the early states and is looking for success (or at least delegates) on Super Tuesday.

Senator Amy Klobuchar of Minnesota has been searching for her share of the moderate vote in the primaries. In Iowa, she banked on name recognition from a state that neighbors her own to give her campaign a lift. Despite a fifth-place-finish, she earned one delegate, which qualified her for the next debate in New Hampshire.

The surge of “Klomentum” did not last. Ms. Klobuchar, like Mr. Buttigieg, struggled to broaden her appeal beyond white voters in the later states. She ended her campaign on Monday and announced an endorsement for Joseph R. Biden Jr.

After watching the race unfold from the sidelines for most of 2019, Michael R. Bloomberg joined the fray in November. The billionaire and former New York City mayor saw an opening as Joseph R. Biden Jr.’s grip on the moderate vote appeared to slip. He decided to skip the first four states and will appear on ballots for the first time on Tuesday.

His fortune has allowed him to run a different race from the other candidates. While they were closing out the campaign in Iowa, he was visiting California. While they were flying to New Hampshire, he was touching down in Pennsylvania, which doesn’t vote until late April.

His path finally converged with the rest of the field’s on the debate stage in Nevada. His rivals hit him with a variety of attacks, from his company’s use of nondisclosure agreements to his promotion of stop-and-frisk policing in New York. Mr. Bloomberg, who had not debated since his last campaign for mayor in 2009, struggled to handle the pressure.

Despite his poor debate performance, he pushed forward. Others camped out in South Carolina, and Mr. Bloomberg visited Super Tuesday states like Tennessee, Texas, Arkansas and Virginia. Along the way he has spent more than $410 million on television advertisements, giving him vast outreach to voters. His unorthodox campaign strategy will be put to the test on Tuesday.