WASHINGTON (Reuters) - The U.S. Senate voted on Friday against calling witnesses and collecting new evidence in President Donald Trump’s impeachment trial, clearing the way for Trump’s almost certain acquittal next week.

By a vote of 51-49, the Republican-controlled Senate stopped Democrats’ drive to hear testimony from witnesses like former national security adviser John Bolton, who is thought to have first-hand knowledge of Trump’s efforts to pressure Ukraine to investigate a political rival, former Vice President Joe Biden.

Those actions prompted the Democratic-controlled House of Representatives to formally charge Trump with abuse of power and obstruction of Congress in December, making Trump only the third president in U.S. history to be impeached.

He denies wrongdoing and has accused Democrats of an “attempted coup.”

The Senate approved on a party-line vote a timeline for the rest of the trial that calls for a final vote on the impeachment charges at 4 p.m. EST (2100 GMT) on Wednesday.

Closing arguments will begin at 11 a.m. EST (1600 GMT) on Monday, with four hours split between the prosecution and defense. That will give the four Democratic senators who are running to be their party’s presidential nominee time to get to Iowa for that night’s first nominating contest.

In between the closing arguments and final vote, senators will have an opportunity to give speeches on the Senate floor, but the trial will not formally be in session. Trump will deliver his State of the Union speech to a joint session of Congress on Tuesday night.

The Senate is almost certain to acquit Trump of the charges, as a two-thirds Senate majority is required to remove Trump and none of the chamber’s 53 Republicans have indicated they will vote to convict.

Trump is seeking re-election in the Nov. 3 vote. Biden is a leading contender for the Democratic nomination to face him.

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In Friday’s vote on witnesses, only two Republicans - Mitt Romney, the 2012 Republican presidential nominee, and Susan Collins, who faces a tough re-election in November in her home state of Maine - broke with their party and voted with Democrats.

“America will remember this day, unfortunately, where the Senate did not live up to its responsibilities, where the Senate turned away from truth and went along with a sham trial,” Senate Democratic Leader Chuck Schumer told reporters.

After the first vote on calling witnesses, Schumer offered more amendments seeking to call witnesses and obtain more evidence, but the Senate rejected them all. Romney and Collins were again the only Republicans to support calling Bolton as a witness.

Republican Senator Lindsey Graham said the trial should end as soon as possible. “The cake is baked and we just need to move as soon as we can to get it behind us,” he told reporters.

NEW DETAILS

Friday’s vote on witnesses came hours after the New York Times reported new details from an unpublished book manuscript written by Bolton in which the former aide said Trump directed him in May to help in a pressure campaign to get Ukraine to pursue investigations that would benefit Trump politically.

Bolton wrote that Trump told him to call Ukrainian President Volodymyr Zelenskiy to ensure Zelenskiy would meet with Trump’s personal lawyer Rudy Giuliani, a key player in the campaign, the Times reported.

Robert Costello, a lawyer for Giuliani, called the Times report “categorically untrue.” Bolton’s lawyer and spokesman did not respond to requests for comment.

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The Times previously reported that Bolton - contradicting Trump’s version of events - wrote the president told him he wanted to freeze $391 million in security aid to Ukraine until Kiev pursued investigations of Democrats, including Biden and his son, Hunter Biden.

Democrats had said the news illustrated the need for the Senate to put Bolton under oath.

But Republicans said they had heard enough. Some said they did not think that Trump did anything wrong, while Senators Lamar Alexander and Rob Portman said his actions were wrong but did not amount to impeachable conduct. Senator Marco Rubio said impeachment would be too divisive for the country, even if a president engaged in clearly impeachable activity.

Lisa Murkowski, a Republican moderate who Democrats had hoped would vote with them to extend the trial, said the case against Trump was rushed and flawed. She told reporters she was “angry at all sides” and the prospect of a tie vote on witnesses weighed heavily on her decision.

After the Senate adjourned on Friday, she said she knew how she would vote on the charges but she would not reveal it yet.

“Will I share it with you tonight? I’ve had so much drama today, I’m just going to chill. How’s that? Was that fair?” Murkowski told reporters.