Representative Jerrold Nadler, Democrat of New York and chairman of the House Judiciary Committee, began the House presentation on Thursday with an hourlong lecture on the constitutional history of impeachment.
He insisted that the history of the Constitution makes it clear that a criminal violation is not necessary to impeach the president. In making the argument, he cited words from some of President Trump’s key allies in his impeachment defense: Alan Dershowitz, a member of the president’s impeachment team; William P. Barr, the attorney general; and Senator Lindsey Graham, Republican of South Carolina.
He concluded his presentation with a forceful assertion to the senators: “Impeachment is aimed at presidents who act as if they are above the law, at presidents who believe their own interests are more important than those of the nation, and thus at president who ignore right and wrong in pursuit of their own gain.”
“Abuse. Betrayal. Corruption,” he said. “Here are the core offenses, the framers feared most. The president’s abuse of power, his betrayal of the national interest, and his corruption of our elections plainly qualified as great and dangerous offenses.”
Drawing on legal scholars and liberally quoting historical figures, Mr. Nadler argued that the founders of the nation envisioned that impeachment would be required for presidential abuses of power like the misconduct the House alleged when it passed two articles of impeachment.
As senators settled in for another long day of arguments from the House managers, there was already talk among lawmakers and their aides of a potentially abbreviated weekend trial schedule.
Under one proposal being discussed, the Senate could convene as a court of impeachment early on Saturday, around 10 a.m. and meet for a far shorter session than usual. That would theoretically allow senators who wanted to travel home — or for Democrats running for president, to campaign in early voting states — for 36 hours before the trial resumes on Monday.
The Senate’s impeachment rules normally require the trial to meet every Monday to Saturday at 1 p.m. until a verdict is reached. That late daily start time is meant to accommodate Chief Justice John G. Roberts Jr., who maintains a morning case schedule at the Supreme Court before presiding over the trial. But Chief Justice Roberts does not have court business on Saturdays.
The decision may also depend on the president’s lawyers, who are scheduled to begin their defense against the House charges on Saturday. If they want to move the trial along as quickly as possible, they could ask for an early start on Saturday but also that the session be allowed to run into the evening. Or they could simply shorten their arguments.
“I suspect we’ll start on Saturday, and then we’ll go, probably another day or two, but who knows,” Jay Sekulow, one of Mr. Trump’s lawyers said Wednesday night. “I mean we’ve got to make that determination, with our team.”
Any change would require consent from both Democrats and Republicans.
Senator Lindsey Graham, Republican of South Carolina and one of the impeachment managers in 1999, left the Senate chamber just minutes before House Democrats played a video of him speaking during President Bill Clinton’s trial.
In the clip, Mr. Graham gave a broad definition of a “high crime”: “It’s just when you’re using your office in a way that hurts people, you’ve committed a high crime,” he said.
One of the Republicans’ talking points is that there was no crime underlying President Trump’s conduct, therefore it was not impeachable. That argument is widely disputed.
Senator John Barrasso, Republican of Wyoming, who sits next to Mr. Graham on the Senate floor, briefly patted the South Carolina Republican’s empty seat as the video began to play.
As Democrats spoke in the Senate, Vice President Mike Pence announced that President Trump had asked him to invite to Prime Minister Benjamin Netanyahu of Israel to Washington next week to discuss “regional issues, as well as the prospect of peace here in the Holy Land.”
Mr. Pence, who is visiting Jerusalem, said at Mr. Netanyahu’s request he had also invited Benny Gantz, an opposition leader in Israel. Mr. Netanyahu said he would “gladly accept.”
It is another instance of the administration moving forward with legislative and diplomatic work while the impeachment trial is going on in the Senate.
On Wednesday, Republican senators held a ceremonial event to formally send Mr. Trump’s revised North American trade pact to his desk for his signature.
Just as Representative Jerrold Nadler of New York, a House manager, started his presentation about “high crimes and misdemeanors,” President Trump started tweeting, accusing Democrats of not wanting to agree to a trade in which the Senate would subpoena several administration officials in exchange for people Mr. Trump’s allies have said they want. Two people Republicans have sought to interview are Hunter Biden, the son of the former vice president, and the anonymous whistle-blower who first expressed concerns about Mr. Trump’s July 25 call with the president of Ukraine.
Democrats have urged the Senate to subpoena John R. Bolton, the former national security adviser, Mick Mulvaney, the acting White House chief of staff, and two other administration officials. But they have said they will not consider a deal that would include what they call irrelevant witnesses like Mr. Biden.
Representative Adam B. Schiff, Democrat of California and the lead impeachment manager, opened the day by observing how rare it was for House lawmakers to have the opportunity to speak on the Senate floor, before silent senators. (Senators have begun flouting the rules of decorum during an impeachment trial, with some going so far as to leave the floor for short bursts of time during the day.)
Chief Justice John G. Roberts Jr. said the House impeachment managers have 16 hours and 42 minutes remaining to make their case.
A Democratic official working on the inquiry said that the seven managers planned to spend the day going through the first article of impeachment, abuse of power, and applying the law and the Constitution to their case. On Friday, the lawmakers plan to do the same with the second article of impeachment.
Moments before the Senate convened, pages could be seen placing packets of paper on desks across the chamber. Senators, ahead of the trial, dropped off binders and bags before stealing a final moment off the chamber floor.
Representative Mary Gay Scanlon, Democrat of Pennsylvania and vice chair of the House Judiciary Committee, could be seen on the Senate floor, observing the proceedings.
The White House named eight House Republicans as part of the public face of the president’s defense on Capitol Hill, and on Thursday some of those lawmakers arrived again in the Senate basement to hold court with reporters and deliver a full-throated defense of the president.
“We’re just making sure that we are paying close attention to the testimony,” said Representative Elise Stefanik, Republican of New York, “and making sure that our points are getting out there to the American people.”
The group, she said, was working closely with the White House lawyers. But since they are not part of the official legal team, they will not be able to speak in the Senate chamber.
The top Democrat in the Senate said he still had “hope” that Republicans would agree to new witnesses and evidence in President Trump’s impeachment trial, but he stopped short of saying he was optimistic that it would happen.
Senator Chuck Schumer of New York, the Democratic leader, said there are “lots of conversations going on,” but he denied reports that there had been discussions with Republicans about a deal allowing Republican witnesses in exchange for the witnesses whom House managers want to call.
Democrats have urged the Senate to call John R. Bolton, the former national security adviser, Mick Mulvaney, the acting White House chief of staff, and two other administration officials. Several moderate Republicans have said they might be open to witnesses after oral arguments and questions from senators.
“Not a single Republican has approached me and said ‘What about this? What about that?’ It’s not happening,” Mr. Schumer told reporters at the Capitol ahead of the second day of oral arguments from the managers.
Mr. Schumer said he hoped the “weight of history” would help persuade those Republicans. But when asked whether he thought the Democrats would win the argument, he started to say he had optimism, then stopped.
“I have hope, that’s a better way to put it,” he said, “that we might get the witnesses at the end of the day. And we’re going to keep fighting and fighting and fighting.”
The president’s personal lawyer, Rudolph W. Giuliani, again promised on Thursday to release more evidence of the widely debunked conspiracy theory implicating one of the president’s top political rivals, former Vice President Joseph R. Biden, in wrongdoing.
Mr. Biden is vying for the Democratic presidential nomination, and the narrative Mr. Giuliani has been promoting is at the center of the impeachment charges against Mr. Trump.
While he’s not on Mr. Trump’s defense team for the Senate trial, Mr. Giuliani is deeply entwined in the pressure campaign on Ukraine that led to the president’s impeachment. And he is among the witnesses who refused to testify during House impeachment inquiry. Mr. Giuliani has said that his work in Ukraine had Mr. Trump’s support.
For the first time since the Senate began hearing arguments against him, President Trump is back in Washington and on Twitter. He tweeted a number of criticisms toward Democrats and their arguments, rehashing favorite insults against his opponents and quoting Fox News personalities.
After returning from the World Economic Forum in Davos, Switzerland, on Wednesday evening, the president is scheduled to travel to Florida on Thursday afternoon just as House managers will begin their second day of arguments.
It is not clear how much of the trial the president has watched live.
The House impeachment managers are set to begin their second day of arguments on Thursday, building on about eight hours already spent arguing that President Trump’s conduct warranted his removal on charges of abuse of power and obstruction of Congress.
Representative Adam B. Schiff, Democrat of California and the lead impeachment manager, told senators that on Thursday they would “go through the law, the Constitution and the facts as they apply to article one” of impeachment.
“We’ve introduced the case, we’ve gone through the chronology and tomorrow we will apply the facts to the law as it pertains to the president’s abuse of power,” Mr. Schiff said as he concluded Wednesday’s arguments.
The impeachment managers have until Friday evening to use their remaining hours of argument time to present before a rancorous Senate. Lawmakers, despite rules threatening imprisonment for talking, have grown increasingly restless while cooped up in the chamber — and few minds appear to be changed.
On Wednesday, the seven lawmakers tasked with presenting the case for Mr. Trump’s conviction took turns outlining the charges that the president attempted to pressure Ukraine for assistance in his re-election campaign by withholding critical military assistance and a White House visit for the country’s leader.
Several Senate Republicans emerged late Wednesday to inform reporters that they had not learned anything new after hours of presentation from the House.