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The Senate on Friday night ushered in the final phase of President Donald Trump's impeachment trial hours after an effort to call witnesses failed largely on party lines, with an all-but-assured acquittal set for next week.

Senators passed a resolution from Senate Majority Leader Mitch McConnell, R-Ky., laying out the rules for closing the roughly two-week-long trial. The resolution, which passed by a vote of 53-47, sets the final vote on Trump's fate for Wednesday at 4 p.m.

Minority Leader Chuck Schumer, D-N.Y., said it was "a grand tragedy" that senators voted against hearing from witnesses.

"No witnesses, no documents in an impeachment trial is a perfidy. It is a grand tragedy. One of the worst tragedies that the Senate has overcome. America will remember this day, unfortunately, where the Senate did not live up to its responsibilities," Schumer said on MSNBC, "where the Senate turned away from truth and went along with a sham trial."

"It's a tragedy on a very large scale," he added.

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Democrats had pressed to hear testimony from acting White House chief of staff Mick Mulvaney and ex-national security adviser John Bolton, among others, on Trump's alleged conditioning of Ukraine aid on investigations into Democrats, including former Vice President Joe Biden. But they failed to get a majority to back their efforts after Sens. Lamar Alexander of Tennessee and Lisa Murkowski of Alaska, two key Republican swing votes, announced that they would not back the move.

The resolution failed 51-49, with GOP Sens. Mitt Romney of Utah and Susan Collins of Maine joining Democrats.

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Shortly before voting on McConnell's resolution, Schumer introduced four amendments in a final effort to call witnesses. The amendments called for the subpoena of witnesses, including Bolton and Mulvaney, and documents that the House had sought from the Office of Management and Budget, the State Department and the Department of Defense. All four amendments failed, largely on party lines. Romney and Collins joined Democrats on the two Bolton amendments.

The White House said that Trump was "gratified" the trial would be ending soon.

McConnell said in a statement Friday that the House managers did not resolve litigation to compel White House aides to testify in the trial.

"A majority of the U.S. Senate has determined that the numerous witnesses and 28,000-plus pages of documents already in evidence are sufficient to judge the House Managers’ accusations and end this impeachment trial," McConnell said. "There is no need for the Senate to re-open the investigation which the House Democratic majority chose to conclude and which the Managers themselves continue to describe as ‘overwhelming’ and ‘beyond any doubt."

The House managers excoriated Republicans who voted against witnesses as having set "a dangerous precedent that will have long-lasting repercussions for the United States Congress, the balance of powers, and our democracy as a whole."

"The truth cannot be denied, not for long, and the facts will continue to come out as they did today," the managers said.

House Speaker Nancy Pelosi, D-Calif., called the Republican senators "accomplices to the President’s cover-up."