Trump impeachment trial: Democrats make 'abuse of power' case

Democrats are about halfway through the 24 hours given for opening arguments.

-House managers make 2nd day of arguments at Senate impeachment trial

-Lead manager Adam Schiff: Focus on first article alleging 'abuse of power'

-President Trump's constitutional lawyer Alan Dershowitz argues a president cannot be impeached for 'abuse of power'

-Schumer says a Trump acquittal will have 'zero value' if no witnesses

-Graham compliments Schiff on presentation of House case, but asks 'will it stand up?

-Nadler: Trump 'puts President Nixon to shame' in abusing power

-Trump legal team concerned Saturday arguments will get buried, may request time change

As the Senate trial of President Donald Trump resumed Thursday afternoon, lead House manager Adam Schiff argued the law and the Constitution, applied to the facts, support the article of impeachment that accuses him of "abuse of power."

On Wednesday, after laying out the timeline of Trump's pressure campaign against Ukraine, including withholding military aid to get Ukraine to announce an investigation of former Vice President Joe Biden and his son, Hunter, Schiff argued that the president violated the Constitution.

Alan Dershowitz, the former Harvard Law School professor who is playing a role on Trump's defense team, is expected to argue, as he's been doing on TV, that a sitting president cannot be impeached for abuse of power as Democrats charge.

Also on Wednesday, the first of three days of opening arguments, Democrats flatly dismissed the notion of offering Joe or Hunter Biden as witnesses in exchange for Trump's former national security adviser John Bolton.

"That trade is not on the table," Senate Minority Leader Chuck Schumer told reporters.

As Thursday's session opened, Chief Justice John Roberts announced that Democrats had 16 hours and 42 minutes left to use over two days before the president's legal team takes the Senate floor on Saturday to begin 24 hours of opening arguments over three days.

The ABC News team of correspondents and producers is covering every aspect of the story.

This is how the day is unfolding. Please refresh for updates.

10:43 p.m. Final statements of the day

In his final statements for the day, Rep. Adam Schiff wrapped up arguments by pointing senators back to the transcript of the Zelenskiy-Trump July 25 phone call, asking senators to view the transcript in the context of the information they'd been listening to all day. Schiff ended on an impassioned note, telling senators that Trump's actions demonstrate that he cannot be trusted to act in the best interest of the country, and telling them that they must remove Trump if they find he is guilty of the actions he's accused of.

Schiff used the end of his time to argue against the narrative that Republicans seem to be getting ready to argue. He asked senators to consider, if Trump is guilty, does he really need to be removed from office for these actions?

"If you find him guilty you must find that he should be removed," Schiff said, "because right matters. Because right matters and the truth matters, otherwise we are lost."

Schiff said Trump's decision to "choose Rudy Giuliani" over the guidance of national security advisers, the FBI and the country shows that Trump is self-interested and cannot be trusted to act in the country's best interest leading up to the election, especially with anticipated election security threats from Russia and China.

"You may be asking, 'How much damage can he really do in the next several months until the election?' Schiff said. "A lot. A lot of damage."

Schiff ended by pointing to remarks from Lt. Col. Alexander Vindman, who said during his House testimony that "right matters." Schiff repeated it multiple times before closing.

"If right doesn't matter, it doesn't matter how good the Constitution is. It doesn't matter how brilliant the framers were. It doesn't matter how good or bad our advocacy in this trial is," he said. "If right doesn't matter, we're lost. If the truth doesn't matter, we're lost."

He also threw some of the president's remarks back at him.

"At the beginning of the trial you may have seen the president tweeted a common refrain: 'Read the transcript,' so I thought at the end of the evening I would join in the president's request that you re-read the transcript because now that you know a lot more of the facts of this scheme it reveals a lot more about that conversation."

-- ABC News' Allie Pecorin

9:42 p.m. Hang in there, Dems say

With Republican senators sounding increasingly irritated by the managers' presentation during their breaks -- telling reporters they are repetitive, etc. -- the managers continued to thank the senators for listening.

House Manager Rep. Zoe Lofgren said, "It's a long day. You are here without your cellphones or any access to other information. It's not easy, but you're paying attention, and the country and the managers thank you for that.

Rep. Jason Crow later echoed the same message as the clock neared 9:30 p.m.: "Just bear with us a little while longer. I promise we are almost there."

Lofgren used her time after a brief recess to detail the hold on military aid to Ukraine, how Trump "knowingly" and "willfully" broke the law by freezing it and how that related to his abuse of power.

"The hold had nothing to do with the national interest. It had to do with the interest of just one person: Donald J Trump. The demand for Ukraine to announce these investigations was not a policy decision but a personal decision by the president to benefit his own personal interests," Lofgren said.

She also pulled out a pocket Constitution to remind senators of their responsibilities.

"Every year we print a new copy of the Constitution and this year in the back we printed a quote. At the conclusion of the Constitutional Convention, Benjamin Franklin was asked, 'What have you wrought?' and he answered, 'A republic, if you can keep it.' That's the challenge that all of us face and that you senators face."

8:43 p.m. 'Doomsday' scenarios for witnesses

Senate Republican leadership is laying the groundwork in its caucus for a vote against subpoenaing witnesses by warning that a guaranteed White House court fight over executive privilege would stall the trial and paralyze the Senate for months.

Former Attorney General Michael Mukasey was called in on Wednesday to lay out the scenarios for GOP senators, sources familiar with the meeting told ABC News.

Mukasey explained how "cumbersome" it would be to subpoena any of the four White House officials sought by the House Democratic managers, the sources said.

Several Republicans in the meeting have told us that they'd expect an executive privilege fight over a Senate trial subpoena to take "weeks or months" leaving the body no choice but to remain idle.

“There’d be nothing else we could do in the interim,” said Sen John Cornyn of Texas. “It would basically hijack the senate. In the meantime, the Senate can't do anything else; we can't confirm judges, we can't have hearings, we can't even introduce legislation.”

Sen. John Barrasso of Wyoming said lawmakers would get an earful from their constituents -- especially independent voters.

"Every day we spend doing this, we're not doing -- I'm a doctor. I want to lower the cost of insulin. I want to deal with this surprise medical billings issue. ... But because we're stuck with this, and the longer you are going, and the longer you're dealing with witnesses, the harder it is to get to the things that I hear about in Wyoming."

-- ABC News' Devin Dwyer

8:25 p.m. Jeffries returns to the mic after break

Rep. Hakeem Jeffries continued speaking when the Senate returned from its break around 7:15 p.m.

Jeffries' presentation got into the minutia of attempts by top officials to get a meeting planned between Trump and Ukrainian President Volodymyr Zelenskiy. He pointed to multiple instances in which the importance of an investigation was emphasized as a necessary concession to getting a meeting scheduled.

"President Trump had immense power over Ukraine and President Trump knew it, so when President Trump asked for a favor on the July 25 call he knew that President Zelenskiy would feel incredible pressure to do exactly what President Trump wanted," Jeffries said.

After displaying text messages between administration officials, Jeffries sampled a portion of the phone call between Trump and Zelenskiy in which Zelenskiy again emphasizes his desire for a White House meeting and spoke to his efforts to possibly pursue "the investigation." Jeffries said the transcript is damning.

"Read the transcript, President Trump says. We have read the transcript and it is damning evidence of a corrupt quid pro quo," Jeffries said. "The evidence against Donald Trump is hiding in plain sight."

Jeffries concluded his comments at 7:47 p.m. -- and Sylvia Garcia took to the podium. She continued presenting evidence laying out attempts by Rudy Giuliani to get confirmation of an investigation, and by administration officials to get a meeting scheduled.

"The evidence is very clear the White House meeting would only be scheduled if Ukraine announced the investigations that everyone, including the Ukrainians, understood to be purely political efforts to benefit the president," Garcia said. "The only way to come to a different conclusion is to ignore the evidence."

-- ABC News' Allie Pecorin

8:08 p.m. Vindman's lawyer slams Sen. Blackburn's tweets attacking client

Following a series of tweets Thursday afternoon by Sen. Marsha Blackburn, R-Tenn., which questioned Lt. Col. Alexander Vindman's motivation to testify and his patriotism, his attorney slammed the comments.

"This difficult moment in our country calls for seriousness and seriousness of purpose," David Pressman, who serves as counsel to the Army officer who defied White House orders and appeared before the House impeachment probe, said in a statement.

"Lieutenant Colonel Alexander Vindman has sacrificed enormously for our country. He believes in our country. And he believes in our country’s great institutions, including the United States Senate," the statement continued. "That a member of the Senate -- at a moment when the Senate is undertaking its most solemn responsibility -- would choose to take to Twitter to spread slander about a member of the military is a testament to cowardice. While Senator Blackburn fires off defamatory tweets, Lieutenant Colonel Vindman will continue to do what he has always done: serve our country dutifully and with honor."

-- ABC News' Benjamin Siegel

6:01 p.m. Democrats argue Giuliani played a key role in ambassador's firing

Over the past hour, House managers Zoe Lofgren and then Val Demings have laid out in detail Rudy Giuliani's efforts, they argue, to conduct shadow diplomacy in Ukraine to further President Trump's political interests, culminating in the firing of Ambassador Marie Yovanovich.

Just as the managers have used Trump's own words against him in clips, this hour of presentation featured multiple videos of Giuliani's prolific media appearances, peddling what Democrats call conspiracy theories, including his comments in this Fox News video clip:

"That there were a group of people in the Ukraine working to help Hillary Clinton and were colluding really with the Clinton campaign and it stems around the ambassador and the embassy being used for political purposes. So I began getting some people that were coming forward and telling me about that. Then all of a sudden they revealed this story about Burisma and Biden's son and Biden's son being on the board," Giuliani said in a Fox News appearance.

Demings and Lofgren use WhatsApp exchanges provided by indicted Giuliani associated Lev Parnas between himself and Giuliani as more evidence that Giuliani pushed for the firing of Yovanovich.

"President Trump removed Ambassador Yovanovitch because she was in the way. She was in the way of the sham investigations that he so desperately wanted. Investigations that would hurt former Vice President Biden and undermine the Mueller investigation into Russia election interference. Investigations that would help him cheat in the 2020 elections," Demings insisted.

And they played the damning bite from EU Ambassador Gordon Sondland, when he admitted that though he believed State Department personnel should take responsibility for Ukraine matters, he felt he had no choice but to conduct diplomacy through Giuliani.

"We chose the latter course, not because we liked it, but because it was the only constructive path open to us," Sondland said in the clip

- ABC News' Sarah Kolinovsky

5:45 p.m. House manager Demings says 'trial bigger than any one election'

House manager Val Demings of Florida countered the Republican accusation that Democrats are trying to skew the 2020 presidential election away from President Trump.

"This trial is much bigger than any one election and it's much bigger than any one president. This moment is about the American people, this moment is about ensuring that every voter, whether a maid or a janitor, whether a nurse or a teacher or a truck driver, whether a doctor or mechanic, that their vote matters and that American elections are decided by the American people," she says.

Some senators appeared restless as the arguments continued in the afternoon session.

GOP Sen. Marsha Blackburn of Tennessee slid her desk drawer open revealing a copy of “Resistance at All Costs” by Kimberly Strassel.

Blackburn also used a blanket to stay warm as did Republican Sen. Shelley Moore Capito of West Virginia.

Sen. Amy Klobuchar of Minnesota enjoyed some chewing gum as she observed Schiff’s performance.

Sen. Richard Burr ordered a glass of milk from a page at 3:31 p.m. Three minutes later, at 3:34 p.m., the milk was delivered to his desk, and he quickly chugged more than half before setting it down. By 3:39 p.m., the milk was fully consumed and a page quickly cleared his empty glass.

I noted at 3:48 p.m. that every senator was at his or her desk. None were standing or absent at that point. Adam Schiff had the room’s full attention.

-ABC News' John Parkinson

It was interesting to watch Schiff seemingly direct parts of his monologue on Ukraine and Russia at Utah Republican Mitt Romney - who is seated in the back row to Schiff’s left.

Romney -- famously a Russia hawk -- appeared riveted as Schiff laid out his argument that Trump's actions toward Ukraine implicates Russia and Putin.

The two seemed to be making eye contact from my vantage point.

Romney was noting line by line down his notepad the enumerated ways that Schiff said Donald Trump “put himself first.”

Overall, the entire chamber seemed to me much more engaged than yesterday afternoon. Most senators on both sides could be seen watching the Democratic slideshow and taking notes.

Only GOP Sen. Tom Cotton of Arkansas was using a fidget spinner, as far as I could tell.

-ABC News' Devin Dwyer

4:50 p.m. Schiff argues Trump was not truly concerned about corruption in Ukraine

As Schiff continues to lay out the Democrats' argument, he targets an expected talking point for the defense -- that Trump was legitimately concerned about corruption within Ukraine.

Schiff argues that then-incoming Ukrainian President Zelenskiy had run on a campaign of reforming corruption, so why was it Trump's focus now instead of on the former administration?

He adds that President Trump badmouthed U.S. Ambassador Marie Yovanovitch in his July 25 call with Zelenskiy, despite her reputation for being a strong corruption-fighter in Ukraine.

He repeats the point that Trump's interest in Ukraine only came after Joe Biden became a rival candidate for the presidency in 2020.

"The evidence is consistent. It establishes clearly that President Trump did not care about corruption, to the contrary he was pursuing a corrupt aim. He wanted Ukraine to do the exact thing that American policy officials have tried for years to stop foreign governments from doing - corrupt investigations of political rivals," Schiff said.

Earlier in the afternoon session, Schiff continued to lay out evidence to support the reasons the Democrats say President Trump put his own personal and political interests ahead of his official responsibilities.

At one point he scrolled through photos of other presidents on calls with world leaders to make a point that the purpose of those calls is to encourage other countries to do what is in the best interest of the country.

Schiff said that when Trump used a call with a foreign leader -- the president of Ukraine-- to push for investigations that would benefit him personally -- it was an abuse of power.

"President Trump abused his authority as commander in chief and chief diplomat to benefit himself and he betrayed the interest of the American people when he did so," Schiff said.

To add to his argument, Schiff cited quotes from the president's personal lawyer, Rudy Giuliani, in The New York Times where Giuliani was quoted saying "someone could say it isn't foreign policy and it's improper" and "my only client is the president of the United States."

2:55 p.m. Trump legal team concerned Saturday arguments will get buried, may request time change

Several GOP sources tell ABC News that senators are actively considering an abbreviated session this Saturday.

The Trump legal team is concerned about their opening arguments getting buried on a Saturday. The situation is fluid, but these same sources tell ABC that the time frame is roughly 10 a.m. until possibly 1 p.m.

“Save 10-1, expect 10-twelvish,” one senior administration official said.

One GOP source said eliminating the Saturday session is also a possibility, but again, the situation is fluid.

When asked whether there would be a short session on Saturday, the president personal attorney, Jay Sekulow, says, "The Senate sets the rules on how we go, so we'll see how that goes."

Prior to now, he's said that "we're going to begin our robust case when the Senate says it's time to start."

Sekulow said that if the Senate wants them to go two hours they will, if they want them to go eight hours, fine -- responding to questions about whether they are saving their major presentation for Monday.

"I am confident that whether it is Saturday or Monday or Tuesday that the case will be made defending the president. I have no doubt," he says.

--ABC News' Trish Turner and Katherine Faulders

2:48 p.m. Democrats: Trump only cared about Ukraine corruption after Biden entered race

House manager Sylvia Garcia lays out evidence the Democrats' say support that Trump abused his power in pushing for investigations into the Bidens and the Ukrainian energy company Burisma.

She says the timeline and lack of evidence that Ukraine interfered in the 2016 election show that Trump's push for the investigations was politically motivated to benefit his campaign and based on Russian misinformation that Ukraine, and not Russia, interfered in American elections.

"What is so dangerous is that President Trump is helping them perpetuate this. Our own president is helping our adversary attack our processes and help his own re-election," she says.

“As soon as President Trump took office, he increased military support to Ukraine in 2017 and in the next year, 2018, but it wasn't until 2019, over three years after Vice President Biden called for Viktor Shokin's removal (Shokin, Ukraine's prosecutor general, was ousted in 2016) --three years after -- that President Trump started pushing Ukraine to investigate his alleged conduct. So what changed? What changed? Why did President Trump not care at all about Biden's request for the removal of Shokin the year after it happened in 2017? Or the next year in 2018? Senators, you know what changed in 2019 -when President Trump suddenly cared -- it is that Biden got in the race. On April 25, Vice President Biden announced he would run for president in 2020," she says.

2:15 p.m. Inside the Senate chamber: Fidget spinners, Graham only senator absent when 1999 clip of him played

Fidget spinners --- that’s apparently one thing you can bring into the Senate chamber for a distraction when you're not allowed to have your cell phone or other electronics.

As the Democratic arguments continue for a second hour, GOP Sen. Richard Burr is the only one who has used his -- on and off so far.

No milk drinkers yet. Republican Sen. Rand Paul has drawn a very impressive sketch of the U.S. Capitol. After further examination, however, it appears he is tracing it. He has placed it on his desk so as to display it to the press above. It’s the only writing on his white legal pad.

GOP Sen. Marcia Blackburn is reading a novel (it's unclear which one) but the book below the current novel she’s reading is “The Case for Trump."

Republican Sen. Cindy Hyde-Smith, who is sitting next to Blackburn, has the book “The Chosen” on her desk, but hasn’t started reading it yet.

Most senators are taking notes and following along with the presentations. They have printouts of the slides and video elements the Democrats are using.

When the clip of Sen. Graham was played Graham was the only senator absent from the chamber. Some Republicans smirked when they looked over and saw he wasn't there.

- ABC News' Katherine Faulders

1:39 p.m. Nadler speaks of the 'ABCs of impeachment'

Nadler boils down the Democratic case to the "ABCs of impeachment."

"Abuse: We will show that President Trump abused his power when he used his office to solicit and pressure Ukraine to meddle in our elections for his personal gain. Betrayal: We will show that he betrayed vital national interests, specifically our national security, by withholding diplomatic support and military aid from Ukraine even as it faced armed Russian aggression. Corruption: President Trump's intent was to corrupt our elections to his personal political benefit. He put his personal interest in retaining power above free and fair elections and above the principle that Americans must govern themselves without interference from abroad.

"Article One thus charges a high crime and misdemeanor that blends abuse of power, betrayal of the nation, and corruption in elections into a single unforgiveable scheme. That is why this president must be removed from office, especially before he continues his effort to corrupt our next election," Nadler says.

Citing legal scholars who agree with the House case, Nadler cites the former Harvard Law School professor who will argue for Trump on the Senate floor that the Constitution does not support that a president can be impeached for abuse of power.

"Another who comes to mind is professor Alan Dershowitz. At least Alan Dershowitz in 1998. Back then here is what he had to say about impeachment for abuse of power," Nadler says before showing a video clip of Dershowitz from 1988.

"It certainly doesn't have to be a crime. If you have somebody who completely corrupts the office of president and who abuses trust and who poses great danger to our liberty, you don't need a technical crime," Dershowitz says in the clip.

"But we need not look to 1998 to find one of President Trump's key allies espousing this view. Consider the comments of our current Attorney General William Barr, a man known for his extraordinarily expansive view of executive power. In Attorney General Barr's view, as expressed about 18 months ago, presidents cannot be indicted or criminally investigated, but that's okay because they can impeached. That's the safeguard," Nadler says as a memo written by Barr in June 2018 appears in exhibits.

"And in an impeachment, Attorney General Barr added, the president is answerable for any abuses of discretion and may be held accountable under law for misdeeds in office. In other words, Attorney General Barr, who believes along with the office of legal counsel that a president may not be indicted believes that that's okay, we don't need that safeguard against a president who would commit abuses of power. It's okay because he can be impeached. That's the safeguard for abuses of discretion and for his misdeeds in office," Nadler quotes Barr as writing.

"When the president betrays our national security and foreign policy interests for his own personal gain, he is unquestionably subject to impeachment and removal," Nadler continues. "The same is true of a different concern raised by the framers, the use of presidential power to corrupt the elections and the office of the presidency. As Madison emphasized, because the presidency was to be administered by a single man, his corruption might be fatal to the republic."

Anticipating another of the arguments from Trump's defense team --- that no specific crime is alleged-- Nadler says, "In a last ditch legal defense of their client, the president's lawyers argue that impeachment and removal are subject to statutory crimes or to offenses against established law, that the president cannot be impeached because he has not committed a crime. This view is completely wrong. It has no support in constitutional text and structure, original meeting, congressional presence, common sense or the consensus of credible experts. In other words, it conflicts with every relevant consideration."

Then, he uses a video clip of GOP Sen. Lindsey Graham, who had left the chamber.

"I might say the same thing of then House manager Lindsey Graham who in President Clinton's trial flatly rejected the notion that impeachable offenses are limited to violation of established law," Nadler says before playing a clip from Graham on the Senate floor in Clinton's 1999 impeachment trail.

"What's a high crime? How about if an important person hurts somebody of low means? It's not very scholarly, but I think it's the truth. I think that's what they meant by high crimes. Doesn't even have to be a crime. It's just when you start using your office and you're acting in a way that hurts people, you have committed a high crime," Graham says in the clip.

1:09 p.m. Nadler: Trump 'puts President Nixon to shame' in abusing power

Rep. Jerry Nadler, D-N.Y., one of the lead House impeachment managers takes the floor after Schiff to begin outlining the charges of abuse of power and obstruction of Congress.

"President Trump used the powers of his office to solicit a foreign nation to interfere in our elections for his own personal benefit. Note, that the act of solicitation itself, just the ask, constitutes an abuse of power. But President Trump went further," he says.

"The president's conduct is wrong. It is illegal. It is dangerous, and it captures the worst fears of our founders and the framers of the Constitution," Nadler says. "No president has ever used his office to compel a foreign nation to help him cheat in our elections. Prior presidents would be shocked to the core by such conduct, and rightly so.

"This presidential stonewalling of Congress is unprecedented in the 238-year history of our constitutional republic. It puts even President Nixon to shame. Taken together, the articles and the evidence conclusively establish that President Trump has placed his own personal political interests first. He has placed them above our national security, above our free and fair elections, and above our system of checks and balances. This conduct is not America first, it is Donald Trump first," Nadler says.

"Donald Trump swore an oath to faithfully execute the laws. That means putting the nation's interests above his own, and the president has repeatedly, flagrantly violated his oath."

1:05 p.m. Schiff: 'There is some method to our madness'

Schiff again took the lead as Democrats begin a second of opening arguments.

But first he offers some humor, possibly referring to reports of restless senators talking and walking around the chamber -- and some leaving.

"I am not sure the chief justice is fully aware of just how rare it is, how extraordinary it is for the House members to be able to command the attention of senators sitting silently for hours or even for minutes for that matter. Of course, it doesn't hurt that the morning starts out every day with a sergeant at arms warning you that if you don't, you will be imprisoned."

Then he outlines how House managers will go through the first article and what he says are the constitutional underpinnings of abuse of power.

"You have now heard hundreds of hours of deposition and live testimony from the House condensed into an abbreviated narrative of the facts. We will now show you these facts and many others and how they are interwoven. You will see some of these facts and videos therefore in a new context, in a new light, in the light of what else we know and why it compels a finding of guilt and conviction, so there is some method to our madness."

12:38 p.m. Graham compliments Schiff on presentation of House case, but asks 'will it stand up?'

Sen. Lindsey Graham, R-S.C., speaks to reporters shortly before Thursday's proceedings begin, and when asked about a reported he had with Schiff after Wednesday's trial session ended, Graham confirms that he complimented Schiff, a fellow former prosecutor, on his presentation.

"He's well-spoken, did a good job of creating a tapestry, taking bits and pieces of evidence and emails and giving a rhetorical flourish making the email come alive," he says. "Quite frankly, I thought they did a good job of taking bits and pieces of the evidence and creating a quilt out of it," he says. "But will it stand up?"

"The point is: let's see what the other side says then we'll make a decision about what the president actually did or didn't do," he adds. "All I can do tell you is it from the presidents point of view, he did nothing wrong, in his mind."

"There are bunch of people on my side who want to call Joe Biden and Hunter Biden. I want to end this thing sooner rather than later," Graham says, explaining he will not vote for witness and documents. "I want the American people to pick the next president not me, and so what I think is the best thing to happen is to have oversight of Ukrainian potential misconduct and move on to the election. I am not going to use my vote to extend the trial," Graham continues.

"I love Joe Biden, but I can tell you, if the name was 'Trump' a lot of questions would be asked."

11:48 a.m. Schumer says a Trump acquittal will have 'zero value' if not witnesses

At a morning news conference, without saying their names, Schumer calls again on four Republican senators -- Lisa Murkowski of Alaska, Susan Collins of Maine, Mitt Romney of Utah and Lamar Alexander of Tennessee -- to join Democrats in calling for witnesses and documents, before directly addressing the president and his GOP allies.

"I will say this to president than any of my Republican friends: if the American people believe this is not a fair trial, which right now they seem to believe because there were no witnesses and documents, acquittal will have zero value to the president or to the Republicans," he says.

"The bottom line is the president is clearly covering up, his people are covering up, and the question is: Will our Republican colleagues rise to their constitutional mandate to create a fair trial?" Schumer adds, "and I don't think it will sit very well with history or with the American people if they don't."

Asked about reports of possible deal on witnesses, Schumer says not a single Republican has approached him on the subject -- further shutting down the idea.

"No Republicans are talking to us about deals. We want these four witnesses ... they go to the truth," he says. (Yesterday, when asked a similar question, Schumer said witnesses should be relevant to the case, seeming to say a deal involving Biden testimony would be off the table for him. Today's answer seems a bit more open-ended.)

--ABC News' Sarah Kolinovsky