Pelosi will meet behind closed doors with House Democrats to decide next steps on Tuesday morning ahead of the party's presidential primary debate that evening, the last before the Iowa caucuses February 3.
House Democrats launched an impeachment inquiry against Trump over a whistle-blower complaint claiming that the president pressed on his Ukrainian counterpart Volodymyr Zelensky to investigate business activities of the former Vice President Joe Biden and his son Hunter in Ukraine.
Last week, McConnell announced that he has enough Republican votes to adopt trial rules that don't immediately allow witnesses.
The trial could open as early as Thursday, beginning with the swearing in of Supreme Court Chief Justice John Roberts as presiding judge.
Trump has denied any wrongdoing and has dismissed his impeachment as a partisan bid to undo his 2016 election win as he tries to win re-election in November.
As things stand, after tomorrow's floor vote in the House, the Senate can vote on its own process, and the general consensus is that the trial in the upper chamber will get under way a week from today.
"That is why Donald Trump has been impeached, because he abused his power". It has nothing to do with the rule of law by any stretch because the articles they came up with don't actually cite any crime.
But in that case Republicans held all the power in Congress against a Democratic president.
In 1999, the Senate trial that followed president Bill Clinton's impeachment over the Lewinsky affair lasted five weeks. The National breaks down what happened, how a divided nation reacted and what happens next.
The case against Trump is focused on a July 25 telephone call in which he asked Ukrainian President Volodymyr Zelensky to open a corruption investigation into Biden and his son Hunter, and into a discredited theory that Ukraine, not Russian Federation, meddled in the 2016 USA election.
The House approved the two articles of impeachment last month. Almost $400 million United States in Pentagon-approved aid to Ukraine, which is fending off Russian military aggression in the east, was held up for several weeks, until a whistleblower complaint about the Trump-Zelensky call became public knowledge.
"We believe we will get 51 votes", Schumer told reporters Tuesday.
"Democrats have called-have asked to call four fact witnesses and subpoena three specific sets of relevant documents related to the president's misconduct with Ukraine".
While some Democrats have grumbled about the delay, Pelosi and other party leaders defended the strategy, saying it produced new potential evidence and turned public attention on the upcoming trial.
Trump has branded the case a "hoax" and a "witch hunt" but the White House is girding for a trial that could present damaging evidence against the USA leader on national television over two weeks or more.
But with McConnell refusing to agree up front on the witness issue, Pelosi made a decision to move ahead.
By voting in favor of calling witnesses and demanding documents, Democrats will necessarily take the chance that the information revealed will help exonerate the president.
Pelosi appeared ready to move ahead after holding onto the articles of impeachment since they were passed on December 18 to pressure the Republican-controlled Senate to agree to subpoena witnesses with direct knowledge of what Trump is charged with: illicitly seeking help from Ukraine for his reelection campaign this year.
Pulitzer Prize-winning journalist David Cay Johnston discusses Sen.
Meanwhile, the president's impeachment legal team is coming together as the trial quickly approaches.