WASHINGTON (AP) — The U.S. House is set to vote Wednesday to send the articles of impeachment against President Donald Trump to the Senate for a landmark trial on whether the charges of abuse of power and obstruction of Congress are grounds for removal.

Speaker Nancy Pelosi announced the next steps after meeting privately with House Democrats at the Capitol, ending her blockade Tuesday a month after they voted to impeach Trump.

It will be only the third presidential impeachment trial in American history, a serious moment coming amid the backdrop of a politically divided nation and an election year.

“The President and the Senators will be held accountable,” Pelosi said in a statement. “The American people deserve the truth, and the Constitution demands a trial.”

The Senate is expected to transform into an impeachment court as early as Thursday. The Constitution calls for the chief justice to preside over senators, who serve as jurors, to swear an oath to deliver “impartial justice.” The House managers will walk the articles across the Capitol in a dramatic procession after the vote.

Senate Majority Leader Mitch McConnell said Tuesday the chief justice would open the trial this week, but that the significant proceedings would launch next Tuesday, after the Martin Luther King Jr. holiday.

Trump was impeached by the Democratic-led House last month on charges of abuse of power over pushing Ukraine to investigate Democratic rival Joe Biden as the president withheld aid from the country, and obstructing Congress’ ensuing probe.

McConnell met behind closed doors Tuesday with GOP senators who are under pressure from Democrats to call new witnesses and testimony. He urged them to hold together on the next steps, according to a person unauthorized to discuss the private session and granted anonymity.

Late Tuesday, House investigators announced they were turning over a “trove” of new records of phone calls, text messages and other information from Lev Parnas, an associate of Trump lawyer Rudy Giuliani. Intelligence Committee Chairman Adam Schiff said the information shows Trump’s effort ”to coerce Ukraine into helping the President’s reelection campaign.” He said this and other new testimony must be included in the Senate trial.

McConnell, who is negotiating rules for the trial proceedings, he said all 53 GOP senators are on board with his plan to start the session and consider the issue of witnesses later.

Senate Republicans also signaled they would reject the idea of simply voting to dismiss the articles of impeachment against Trump, as the president has suggested. McConnell agreed he does not have the votes to do that.

“There is little or no sentiment in the Republican conference for a motion to dismiss,” McConnell said. ”Our members feel we have an obligation to listen to the arguments.”

In fact, a mounting number of senators say they want to ensure the ground rules include the possibility of calling new witnesses.

Sen. Susan Collins of Maine is leading an effort among some Republicans, including Mitt Romney of Utah and Lisa Murkowski of Alaska for witness votes.

“My position is that there should be a vote on whether or not witnesses should be called,” Collins said.

Romney said he wants to hear from John Bolton, the former national security adviser at the White House, who others have said raised alarms about the alternative foreign policy toward Ukraine being run by Trump’s personal lawyer Rudy Giuliani.