Democratic West Virginia Sen. Joe Manchin, speaking on the Senate floor about the impeachment efforts Monday, urged his colleagues to formally censure President Trump -- saying that while the president's dealings with both Ukraine and Congress were "simply wrong," he is "struggling" over whether to vote to convict and remove him from office and potentially "tear the country apart."

At the same time, Manchin also condemned the Republican-controlled Senate for failing to call additional witnesses in the impeachment trial, saying "history will judge the Senate harshly" for failing its constitutional duty to "protect our democracy."

"Never before in the history of our republic has there been a purely partisan impeachment vote of a president," said Manchin, who represents a deeply pro-Trump state. "Removing this president at this time would not only further divide our deeply divided nation, but also further poison our already toxic political atmosphere."

READ MANCHIN'S PROPOSED CENSURE RESOLUTION

He added: "I see no path to the 67 votes [requried to convict and remove] President Trump. However, I do believe a bipartisan majority of this body would vote to censure President Trump. ... Censure would allow this body to unite across party lines."

A censure resolution, which Manchin said, “would allow a bipartisan statement condemning [Trump's] unacceptable behavior in the strongest terms," has no practical effect and serves as a legislative rebuke to the sitting president.

Saying the decision of whether to remove Trump from office was a "grave" matter that has "weighed heavily" on him, Manchin noted he has "listened carefully" to both sides of the issue -- and that he remains undecided.

"The president asked a foreign government to intervene in our upcoming election," Manchin said. "He defied lawful subpoenas from the House of Representatives."

GOP-CONTROLLED SENATE NARROWLY REJECTS MORE WITNESSES IN IMPEACHMENT TRIAL, PAVING WAY FOR ACQUITTAL

Trump is all but assured to be acquitted on Wednesday in the GOP-controlled Senate, where a two-thirds vote would be required to remove the president.

Closing arguments Monday in the impeachment trial were largely directed more toward history than to sway the outcome, one final chance to influence public opinion and set the record ahead of Trump's expected acquittal.

The House Democratic prosecutors drew on the Founding Fathers and common sense to urge senators — and Americans — to see that Trump's actions are not isolated but a pattern of behavior that, left unchecked, will allow him to "cheat"' in the 2020 election.

California Democratic Rep. Adam Schiff implored those few Republican senators who have acknowledged Trump's wrongdoing in the Ukraine matter to prevent a “runaway presidency” and stand up to say “enough.”

WHAT IS HAPPENING IN IOWA? PRANKSTERS TROLL DEMS AHEAD OF KEY VOTE

“For a man like Donald J. Trump, they gave you a remedy and meant for you to use it. They gave you an oath, and they meant for you to observe it,” Schiff said. "We have proven Donald Trump guilty. Now do impartial justice and convict him.”

The president's defense countered the Democrats have been out to impeach Trump since the start of his presidency, nothing short of an effort to undo the 2016 election and to try to shape the next one, as early primary voting begins Monday in Iowa.

CLICK HERE TO GET THE FOX NEWS APP

“Leave it to the voters to choose,” said White House counsel Pat Cipollone.

He called for an end to the partisan “era of impeachment.”

Fox News' Chad Pergram and The Associated Press contributed to this report.