Senate Minority Leader Chuck Schumer said Senate Democrats and House impeachment managers are unlikely to convince the four Republican senators they need to vote for additional witnesses in President Trump's impeachment trial.

“The president and Mitch McConnell put huge pressure on these folks,” Schumer told reporters Wednesday. “So I hope we can get witnesses and documents. It’s an uphill fight. Is it more likely than not? Probably no. But is it a decent, good chance? Yes.”

Impeachment managers have spent the last week arguing that additional witnesses and documents not gathered during the House impeachment investigation into Trump should be included in the evidence senators consider before voting on whether to remove him from office.

House Democrats impeached Trump on two charges, abuse of power and obstruction of Congress, after an investigation found Trump pressured a foreign leader to investigate his political rivals.

The top witness Democrats want to hear from is John Bolton, Trump's national security adviser, who claims the president discussed a freeze on military aid to the country with him.

Democrats say Bolton's claims are a clear example of a "quid pro quo" Trump engaged in.

Trump has called his impeachment a "hoax" and threatened potential Republican defectors on Twitter.



Remember Republicans, the Democrats already had 17 witnesses, we were given NONE! Witnesses are up to the House, not up to the Senate. Don’t let the Dems play you! — Donald J. Trump (@realDonaldTrump) January 29, 2020



Before the trial began, the New York Democrat forced votes during a hearing on the rules of the road for the trial, asking that additional witnesses be called.

"Well, look, it's clear that McConnell's rules caused the trial to be rushed with as little evidence as possible in the dark of night," Schumer has said. "They do not want the evidence to come out."

House impeachment manager Rep. Jerry Nadler has said if Republicans do not allow for additional witnesses, they are complicit in covering up the crimes Trump is alleged to have committed.

"The Senate is on trial," Nadler warned before the proceedings began.

After several days of opening arguments, Schumer said House managers made "a really compelling case for why the Senate should call witnesses and documents.”

Still, Senate Majority Leader Mitch McConnell has promised to bring the trial to a quick conclusion and put an end to what he and other defenders of Trump have called a "sham" impeachment process that lacks in merit.

McConnell indicated Tuesday he did not yet have the votes to kill additional witness testimony, but multiple reports since have suggested he is getting closer to achieving that goal.

Sen. Lindsey Graham, another leading Trump defender, predicted the trial will come to an end as soon as the end of the week.

A vote on whether to call additional witnesses is expected Friday.

