WASHINGTON — House Speaker Nancy Pelosi said the House will take steps next week to send articles of impeachment to the Senate, ending Democrats’ blockade of President Donald Trump’s Senate trial.

In a letter to her Democratic colleagues, Pelosi said Friday she was proud of their ‘’courage and patriotism” and warned that senators now have a choice as they consider the charges of abuse and obstruction against the president.

“In an impeachment trial, every Senator takes an oath to do ‘impartial justice according to the Constitution and laws,’’ Pelosi wrote. “Every Senator now faces a choice: to be loyal to the President or the Constitution.”

The move could mean the trial starts as soon as next week. Senate Majority Leader Mitch McConnell said Friday afternoon that the Senate is “anxious to get started” and “we’ll get about it as soon as we can.”

Soon after Pelosi sent out the letter, Trump criticized her in an interview with Laura Ingraham of Fox News. He said that it was “ridiculous” that she withheld the articles.

“She should have sent them a long time ago. It just belittles the process,” Trump said. “Nancy Pelosi will go down as the least successful speaker of the House in the history of our nation.”

The president also expressed concern about former national security adviser John Bolton’s announcement that he would testify in the Senate trial if called. Asked if he would invoke executive privilege to stop it, Trump said, “Well I think you have to for the sake of the office.”

Chuck Cooper, an attorney for Bolton, declined to comment.

Bolton was present for several of the internal White House discussions about Ukraine policy that were at the heart of the Democrats’ impeachment case. The president faces charges of abuse and obstruction over his efforts to urge Ukraine to investigate Democrats.

Since the House vote on Dec. 18 to impeach the president, Pelosi has been in a standoff with McConnell that has consumed Capitol Hill and scrambled the political dynamics. She said she did not want to send the articles to the Senate unless she knew there would be a fair trial with witness testimony.

Pelosi also asked McConnell for details on the structure of the trial so she could decide who to appoint as impeachment managers. McConnell never provided them.

On Friday, Pelosi ended the stalemate by saying  she had asked House Judiciary Committee Chairman Jerrold Nadler to be prepared to bring to the floor next week a resolution to appoint managers and transmit the articles of impeachment to the Senate.

“I will be consulting with you at our Tuesday House Democratic Caucus meeting on how we proceed further,” Pelosi wrote in the letter to her colleagues. She did not announce a date for the House vote.

The move eases for now the protracted showdown between Pelosi and McConnell over the rare impeachment trial, only the third in the nation’s history.

Transmittal of the documents and naming of House impeachment managers are the next steps needed to start the Senate trial. Yet questions remain in the Senate on the scope and duration.

McConnell wants to launch a speedy trial without new witnesses but Democrats point to new evidence that has emerged as they press for fresh testimony, as well as Bolton’s willingness to testify.

Despite McConnell’s wishes for a speedy trial, some Republicans in his caucus have indicated that they are open to witnesses.