A trial of Trump can't begin in the Senate until it receives the abuse of power and obstruction measures passed by the House on Wednesday.
Senate Majority Leader Mitch McConnell, R-Ky., will say Thursday that House Speaker Nancy Pelosi, D-Calif., "may be too afraid" to send the articles of impeachment to the Senate after the speaker suggested she won't submit them until she believes a fair trial will take place.
McConnell will lambaste the impeachment from the Senate floor as "the most rushed, least thorough, and most unfair ... in modern history," according to excerpts of his floor remarks released ahead of the speech.
The two articles of impeachment approved by the House on Wednesday charge Trump with abuse of power and obstruction of Congress.
McConnell will say those articles are "fundamentally unlike any articles that any prior House of Representatives has ever passed" and the idea Democrats will withhold the articles suggests "House Democrats may be too afraid to even transmit their shoddy work product to the Senate."
"The framers built the Senate to provide stability," McConnell will say. "To keep partisan passions from boiling over. Moments like this are why the United States Senate exists."
Trump also expressed disdain over the idea that Democrats may not immediately submit the articles, tweeting on Thursday: "Now the Do Nothing Party want to Do Nothing with the Articles & not deliver them to the Senate, but it's Senate's call!"
"The Senate shall set the time and place of the trial," he said. "If the Do Nothing Democrats decide, in their great wisdom, not to show up, they would lose by Default!"
The articles must be transmitted to the Senate before such a trial could begin.
Pelosi on Wednesday excoriated McConnell for pledging "total coordination" with the White House for the coming Senate trial, which she compared to the foreman of a jury's being in "cahoots" with the defendant's attorney.
"We're not sending (the articles) tonight because it's difficult to determine who the managers would be until we see the arena in which we will be participating," Pelosi said, adding, "So far, we haven't seen anything that looks fair to us, so hopefully it will be fairer, and when we see what that is, we'll send our managers."
Sen. Lindsey Graham, R-S.C., tweeted that such withholding of the articles of impeachment "would be a breathtaking violation of the Constitution, an act of political cowardice, and fundamentally unfair to" Trump.
"Not allowing the Senate to act on approved Articles of Impeachment becomes Constitutional extortion and creates chaos for the presidency," he continued.
Earlier this week, Senate Minority Leader Chuck Schumer, D-N.Y., proposed calling four Trump administration witnesses, including former national security adviser John Bolton and acting White House chief of staff Mick Mulvaney at the Senate trial. House Democrats previously subpoenaed all four officials, who did not testify.
"There's not a single reason that has been given why the four witnesses we've asked for, why the documents we've asked for, should not be presented," Schumer told MSNBC's "Morning Joe" on Monday. "I don't know what they'll say. Maybe they'll be exculpatory to President Trump. But to not have them is to engage in a cover up."
In response, McConnell said it's "not the Senate's job to leap into the breach and search desperately for ways to get to guilty."