Speaker of the House Nancy Pelosi, D-Calif., joined by House Intelligence Committee Chairman Adam Schiff, D-Calif., right
Speaker of the House Nancy Pelosi, D-Calif., joined by House Intelligence Committee Chairman Adam Schiff, D-Calif., right, leaves a lengthy closed-door meeting with the Democratic Caucus at the Capitol in Washington, Jan. 14, 2020.

CAPITOL HILL - The U.S. House of Representatives is set to vote Wednesday on sending articles of impeachment against President Donald Trump to the Senate for a trial that is expected to begin in earnest next week.

The House approved the impeachment articles last month, but Speaker Nancy Pelosi delayed submitting them as House Democrats tried to get Senate leaders to agree to allow testimony from new witnesses during the trial.

That matter remains unresolved.  Senate Majority Leader Mitch McConnell has resisted the idea of calling witnesses and said the decision would come later in the trial.

"We'll deal with the witness issue at the appropriate time during the trial - both sides will want to call witnesses they want to hear from,” McConnell told reporters on Capitol Hill Tuesday.

He also criticized House Democrats, saying they cannot both argue that the case to impeach Trump was strong, "but also so weak that the Senate needs to go fishing."

Pelosi said if the Senate launches the trial without witnesses, the American people will see it "as a pure political cover-up."

"Leader McConnell and the President are afraid of more facts coming to light," she said.

U.S. Senate Majority Leader Mitch McConnell speaks to Capitol Hill reporters following the weekly Senate Republican policy lunch at the U.S. Capitol in Washington, Jan. 14, 2020.

After the vote Wednesday, the lawmakers who will act as prosecutors will walk the articles of impeachment to the Senate side of the Capitol.

Those House impeachment managers will also be named Wednesday, and are likely to include Intelligence Committee Chairman Adam Schiff and Judiciary Committee Chairman Jerrold Nadler.

Preliminary trial steps would then follow this week, with the actual trial itself beginning Tuesday and likely lasting several weeks.

Trump is accused of abusing his power by pressuring Ukraine to investigate former Vice President Joe Biden and his son, Hunter, who served on the board of a gas company in Ukraine, as Trump withheld $391 million in aide that he later released.  The president is also accused of subsequently obstructing a congressional probe into his actions.

Trump insists he did nothing wrong and has dismissed the impeachment effort as a "witch hunt."

"While we're creating jobs and killing terrorists, Democrats in Congress are wasting America's time with demented hoaxes and crazy witch hunts," he told supporters at a Tuesday night rally.

President Donald Trump speaks at a campaign rally Tuesday, Jan. 14, 2020, in Milwaukee.

No matter what rules are in place for the Senate trial, Trump seems to be safe from the prospect of being convicted and removed from office.

His Republican Party holds a 53 to 47 majority in the chamber, and conviction requires a two-thirds majority, meaning if all Democrats voted to convict then 20 Republicans would have to also vote that way for Trump to lose the presidency.

Democrats said late Tuesday that along with the impeachment articles they will include new evidence provided by Florida businessman Lev Parnas, an associate of Trump's personal lawyer Rudy Giuliani.

The evidence includes a screenshot of a previously undisclosed letter Giuliani sent in May to the then president-elect, introducing himself as Trump's "personal counsel" and requesting a meeting with Trump’s "knowledge and consent."

It also includes communications between Parnas, Giuliani and others about the firing of U.S. Ambassador to Ukraine Marie Yovanovich, who balked at Trump's demand for an investigation of the Bidens.

This is the third time in the country’s 244-year history a U.S. president has been impeached and targeted for removal from office.

Andrew Johnson in 1868 and Bill Clinton in 1998 were both impeached by the House but acquitted in Senate trials. A fourth president, Richard Nixon, resigned in 1974 in the face of certain impeachment in a political corruption scandal.