Trump complained anew it was all a “hoax,” even as fresh details emerged about his efforts in Ukraine.

The ceremonial pomp and protocol by lawmakers who will be prosecuting the case against Trump moved the impeachment out of Speaker Nancy Pelosi’s Democratic-run House to the Republican-majority Senate, where the president’s team is mounting a defense aiming for swift acquittal.

“Today we will make history,” Pelosi said as she signed the documents, using multiple pens to hand out and mark the moment. “This president will be held accountable.”

Earlier Wednesday, the House voted 228-193, almost entirely along party lines to deliver the charges. The split reflected the deeply divided nation at the start of this presidential election year. It came one month after the House impeached Trump alleging he abused his presidential power by pressuring Ukraine to investigate Democratic rival Joe Biden, using military aid to the country as leverage. Trump was also charged with obstructing Congress’ ensuing probe.

Trump’s political campaign dismissed the House effort as “just a failed attempt to politically damage President Trump leading up to his reelection.”

The Senate will transform itself into an impeachment court on Thursday. The Constitution calls for Chief Justice John Roberts to preside at the trial, administering the oath to senators who will serve as jurors and swear to deliver “impartial justice.’

Technically, the House was simply notifying the Senate of its delivery of the articles, with a more formal presentation Thursday. Opening arguments are to begin next Tuesday after the Martin Luther King Jr. holiday.

The top Republican in the House, Kevin McCarthy of California, said Americans will look back on this “sad saga” that tried to remove the president from office with the “weakest case.”

The president’s team expects acquittal with a Senate trial lasting no more than two weeks, according to senior administration officials unauthorized to discuss the matter and granted anonymity.

That’s far shorter than the last presidential impeachment trail, of Bill Clinton, in 1999, or the first one, of Andrew Johnson, in 1868.

As Senate Majority Leader Mitch McConnell sets the rules for the trial, Trump has given mixed messages about whether he prefers lengthy or swift proceeding, and senators are under pressure with the emerging new evidence to call more witnesses for testimony.

The seven-member prosecution team will be led by the chairmen of the House impeachment proceedings, Reps. Adam Schiff of the Intelligence Committee and Jerry Nadler of the Judiciary Committee, two of Pelosi’s top lieutenants.

Ahead of Wednesday’s session, Schiff released new records from Lev Parnas, an associate of Trump lawyer Rudy Giuliani, about the Ukraine strategy, including an exchange with another man about surveilling later-fired Ambassador Maria Yovanovitch.

Schiff said the new evidence should bring more pressure on McConnell, who is reluctant to allow witnesses to testify and also prefers swift acquittal.

“If McConnell makes this the first trial in history without witnesses, it will be exposed for what it is and that is an effort to cover up for the president,” Schiff said.

McConnell opened the Senate dismissing what he called a rushed impeachment that is more about the politics of Democrats who don’t like Trump than the charges against him.

“This isn’t really about Ukraine policy or military money,” McConnell said. “This has been naked partisanship all along.”

Trump’s trial will be only the third presidential impeachment trial in U.S. history, and it comes against the backdrop of a politically divided nation in an election year.

The managers are a diverse group with legal, law enforcement and military experience, including Hakeem Jeffries of New York, Sylvia Garcia of Texas, Val Demings of Florida, Jason Crow of Colorado and Zoe Lofgren of California.

Two are freshmen lawmakers — Crow a former Army Ranger who served in Iraq and Afghanistan, Garcia a former judge in Houston. Demings is the former police chief of Orlando and Jeffries is a lawyer and member of party leadership. Lofgren has the rare credential of having worked on the congressional staff investigation of then-President Richard Nixon’s impeachment — he resigned before the full House voted on the charges — and then being an elected lawmaker during Bill Clinton’s.

All but one Democrat, Rep. Collin Peterson of Minnesota, voted to transmit the articles. All Republicans voted against. One former Republican-turned-independent, Rep. Justin Amash of Michigan, joined Democrats.

McConnell faces competing pressures from his party for more witnesses, from centrists who are siding with Democrats on the need to hear testimony and conservatives mounting Trump’s defense.

Senate Republicans signaled they would reject the idea of simply voting to dismiss the articles of impeachment against Trump, as Trump himself has suggested. McConnell agreed he does not have the votes to do that.

Sen. Susan Collins of Maine is leading an effort among some Republicans, including Mitt Romney of Utah, Lisa Murkowski of Alaska and Lamar Alexander of Tennesse e to consider Senate witnesses. She told reporters she was satisfied the rules will allow votes on that.

Romney said he wants to hear from John Bolton, the former national security adviser at the White House, who others have said raised alarms about the alternative foreign policy toward Ukraine being run by Giuliani.

Those four senators could force votes. Republicans control the chamber, 53-47, and are all but certain to acquit Trump. But it takes just 51 votes during the trial to approve rules or call witnesses. It also would take only 51 senators to vote to dismiss the charges against Trump.

Sen. Rand Paul of Kentucky and other Republicans want to subpoena Biden and his son, Hunter, who served on the board of a gas company in Ukraine, Burisma, while his father was vice president.

McConnell prefers to model Trump’s trial partly on the process used for Clinton’s impeachment trial in 1999. It, too, contained motions for dismissal or calling new witnesses.

McConnell is hesitant to call new witnesses who would prolong the trial and put vulnerable senators who are up for reelection in 2020 in a bind with tough choices. At the same time, he wants to give those same senators ample room to show voters they are listening.

More must-read stories from Fortune:

—Donald Trump and the power of incumbency
—Just six candidates qualify for the January Democratic debate
—The wealthiest members of Congress—and how they made their millions
—USPS could privatize as early as next year
—2020 Crystal Ball: Predictions for the economy, politics, technology, and more
Get up to speed on your morning commute with Fortune’s CEO Daily newsletter.