WASHINGTON — The White House signaled on Friday that it did not intend to mount a defense of President Trump or otherwise participate in the House impeachment proceedings, sending a sharply worded letter to Democrats condemning the process as “completely baseless” and urging them to get it over with quickly.
“House Democrats have wasted enough of America’s time with this charade,” the White House counsel, Pat A. Cipollone, wrote in a letter to the House Judiciary Committee chairman, Representative Jerrold Nadler of New York. “You should end this inquiry now and not waste even more time with additional hearings.”
The letter did not explicitly say what Mr. Trump’s legal team planned to do, but it ended by quoting the president saying that the House should hold a swift vote on impeachment to speed the way for a trial in the Republican-controlled Senate, where White House officials believe Mr. Trump will have a better chance to mount a defense. People close to the White House said that it would take major concessions by Democrats for that position to change.
That timetable also suits House Democrats, who have signaled they want to move quickly to impeach Mr. Trump before leaving Washington for Christmas.
The White House position most likely clears the way for House committees to debate and approve impeachment articles as soon as next week, allowing a vote by the full House by Dec. 20, the final legislative day of the year. And it all but ensures that the president’s defense will not be heard before early January, when the Senate is expected to begin a trial to hear whatever case the House presents.
“Adopting articles of impeachment would be a reckless abuse of power by House Democrats and would constitute the most unjust, highly partisan and unconstitutional attempt at impeachment in our nation’s history,” Mr. Cipollone wrote.
The White House stance is a departure from impeachments past. When the House moved to charge Presidents Richard M. Nixon and Bill Clinton, their lawyers fully participated in the proceedings, including presenting lengthy defenses before the Judiciary Committee.
In the case of Mr. Trump, the president and his allies have complained for months that they deserve legal representation in the inquiry. Now, they are refusing an invitation to avail themselves.
House Republicans, who are shouldering the weight of defending Mr. Trump in the White House’s absence, took a different approach in a letter of their own on Friday. Representative Doug Collins of Georgia, the top Republican on the panel, asked Mr. Nadler to allow testimony by at least eight witnesses who have become outsize figures in the president’s defense, “to provide context and transparency about the underlying facts at issue in this ‘impeachment inquiry.’”
First on the list was Representative Adam B. Schiff, Democrat of California and the chairman of the House Intelligence Committee, whose investigation is likely to form the basis for impeachment articles. Mr. Schiff’s team concluded that Mr. Trump sought to pressure Ukraine to investigate former Vice President Joseph R. Biden Jr., his son Hunter Biden and a theory that Democrats conspired with Ukraine to interfere in the 2016 election, withholding as leverage a coveted White House meeting and $391 million in military aid.
Mr. Collins argued Mr. Schiff should have to face questions about his work.
Others on the list included the anonymous C.I.A. whistle-blower whose complaint about Mr. Trump’s dealings with Ukraine prompted the impeachment inquiry, along with any government officials whose accounts informed his account. Republicans want to hear from Hunter Biden, who sat on the board of a Ukrainian energy company while his father was vice president, and his business partner; and a former Democratic National Committee staff member who news reports have indicated had contact with Ukrainian officials in Washington during the 2016 campaign.
“That will be necessary to ensure at least a modicum of fairness and due process is afforded to the president, and, more importantly, the American electorate,” Mr. Collins wrote.
Three powerful Senate Republicans seemed to have similar targets in mind on Friday. Senator Ron Johnson of Wisconsin, the chairman of the Homeland Security Committee; Senator Lindsey Graham of South Carolina, the chairman of the Judiciary Committee; and Senator Charles E. Grassley of Iowa, the chairman of the Finance Committee, jointly requested testimony and documents from the former Democratic National Committee aide, Alexandra Chalupa, and a former Ukrainian Embassy official.
“Contrary to the popular narrative in the ‘mainstream media’ that Ukrainian involvement in the 2016 election has been debunked, or ‘no evidence exists,’ there are many unanswered questions that have festered for years,” Mr. Johnson said in a statement. “Those who are curious have a legitimate and understandable desire to know if wrongdoing occurred.”
Mr. Nadler had set a deadline of Friday evening for the White House to state whether it intended to mount a defense before the panel and for Republicans to recommend witnesses. Democrats are almost certain to vote down the requests from Mr. Collins.
The missives came the day after Speaker Nancy Pelosi announced that she was directing senior Democrats to begin drafting impeachment articles against Mr. Trump.
The Judiciary Committee held its first impeachment hearing this week, convening a panel of constitutional scholars to discuss the history and meaning of impeachment. The panel will hold another session on Monday to receive and debate the findings from the House Intelligence Committee’s two-month investigation of Mr. Trump’s attempts to pressure Ukraine to investigate his political rivals.
Nicholas Fandos reported from Washington, and Maggie Haberman from New York. Catie Edmondson contributed reporting from Washington.