WASHINGTON — Almost from the moment that Speaker Nancy Pelosi and her lieutenants decided this fall to pursue the impeachment of President Trump, they made a fateful judgment: If the president intended to do nothing but stonewall and subvert their inquiry, they were not going to be the ones politely sticking to lofty traditions.
Mr. Trump’s lawyers have made a similarly cold calculation. After a year of defying without consequence Congress’s attempts to investigate the president’s conduct, they have no intention of taking part in what they view as an illegitimate impeachment, initially conducted without a formal House vote in a break with recent precedent.
The clash comes to a head on Monday with a hearing in the Judiciary Committee where Democratic lawyers plan to present the case for impeaching Mr. Trump while the White House sits out the process. That will set in motion a rapid-fire set of actions likely to produce official charges against the president by week’s end and a nearly party-line vote in the full House before Christmas to impeach him.
It is an indication of how, in a deeply polarized nation where party rules above all else, a process enshrined in the Constitution as the most consequential way to address a president’s wrongdoing has devolved into another raucous partisan brawl.
“That is a tragedy,” said Philip Bobbitt, a Columbia University law professor and a leading expert on the history of impeachment. The framers of the Constitution were careful to design a process for removing a president from office that they hoped would rise above the nation’s petty political squabbles, he said.
“They did everything possible to prevent that from happening, and we are plunging headlong into it,” Mr. Bobbitt said.
Determined not to let Mr. Trump and his Republican allies in Congress derail their efforts with legal delays or time-consuming diversions, Democrats have decided it is not worth waiting for cooperation they are all but certain not to receive as they press forward to charge the president with high crimes and misdemeanors.
Democrats argue that they have gone out of their way to treat Mr. Trump fairly but been refused at every turn. As recently as last week, lawyers for the Judiciary Committee privately called the White House counsel’s office, urging the president’s legal team to participate in their hearings and seeking to arrange the logistics, according to Democratic officials familiar with the calls.
Lawmakers are set to begin debating articles of impeachment this week — with House Judiciary Committee members bracing for the possibility of late-night sessions in an office building near the Capitol — as they race to complete a streamlined proceeding based on their conclusion that Mr. Trump abused his power by trying to solicit help from Ukraine in the 2020 re-election.
Upset by the rapid pace of the inquiry and frustrated by Democratic rules he says are unfair — including the lack of subpoena power for the White House — Mr. Trump is simply refusing to engage. In a significant departure from previous impeachments, Mr. Trump’s lawyer signaled in a letter on Friday that the president would not take part in the House proceedings.
While Democrats who control the House are focused on a swift impeachment vote by year’s end, the White House is almost entirely consumed by the trial that would follow in the Republican-controlled Senate, where Mr. Trump’s team believes he would have the chance to defend himself and where Democrats would almost certainly fall short of the two-thirds vote they would need to remove him from office.
That proceeding, however, is also full of unknowns. At a meeting with senior White House officials and senators in the Roosevelt Room of the White House almost three weeks ago, Senator Ted Cruz, Republican of Texas, made clear that there are not enough Senate votes to approve some of the edgier witnesses that Democrats and Republicans want to call. While he mentioned no names, it was interpreted by those in the room to refer to people like Hunter Biden, the son of the former vice president, whom Mr. Trump pushed Ukraine to investigate.
In the House, though, the president is eager to see Republicans and his lawyers mount a robust assault on what he calls a “hoax” and a “scam” led by “crazy” and “dishonest” Democrats.
“What they are doing here is discrediting a system,” Mr. Bobbitt said of the White House impeachment strategy. “If the system is discredited, it cannot discredit me. It is brilliant in its way, but totally cynical and completely destructive of our values.”
Politics have always been a powerful factor in presidential impeachment inquiries, which have roiled the nation twice in the last 50 years.
But impeachment has occupied a special place in the American consciousness. Veterans of the process said there had been an understanding, even amid bouts of intense political combat, that both sides had an obligation to the Constitution that should be honored, regardless of partisan affiliation.
“No one was looking at the other side with the kind of contempt that both sides look at each other now,” said Julian Epstein, who served as the chief Democratic counsel to the House Judiciary Committee when Republicans tried to force Mr. Clinton from office.
Mr. Epstein fought fiercely to defend Mr. Clinton, but also worked closely on the process with his adversaries, including Paul J. McNulty, the chief counsel and spokesman for the committee Republicans. Mr. McNulty, now a college president, said the fight over impeachment had gone from “partisan but constructive” in 1998 to “partisan and destructive” now.
Both men said the biggest risk was that the process would get so damaged, and the personal attacks so severe, that impeachment would be seen in the future as just another partisan weapon to be deployed against every president.
“It becomes a quadrennial tool of political combat,” Mr. Epstein lamented, comparing the future of impeachment to the series of English civil wars for control of the throne in the 15th century. “Each side will try to find something on the other, and it will never end. It’s like a ‘War of the Roses’ that goes on forever.”
The dynamic was different in the summer of 1974, when a bipartisan majority of lawmakers in the House prepared to impeach President Richard M. Nixon for the Watergate burglary and its cover-up. Mr. Nixon resigned before the vote, but there was broad consensus in the House, and in the country, about what needed to happen. By the time Mr. Nixon left, just 24 percent of the country approved of the job he was doing.
Twenty-four years later, as lawmakers grappled with whether to impeach Mr. Clinton, the rancor in Washington had deepened. Led by Speaker Newt Gingrich, Republicans seized on impeachment to bludgeon the popular Democratic president. Democrats accused Ken Starr, the independent counsel, of a witch hunt and insisted that the president’s decision to lie about his affair with an intern was not impeachable.
But partisanship — however raw and ugly — had not yet entirely consumed the process. There were Democrats who parted ways with Mr. Clinton and supported that inquiry. By contrast, when the House voted this October to lay out rules for Mr. Trump’s impeachment inquiry, not a single Republican supported it.
“While we never thought that the Democrats would support impeaching Clinton, we bent over backward to be procedurally fair,” said Representative Jim Sensenbrenner, Republican of Wisconsin and a member of the Judiciary Committee, who was one of the impeachment managers presenting the case against Mr. Clinton in the Senate in 1999. “That’s not happening this time.”
Democrats are unapologetic, vowing not to relent in their march toward impeachment and dismissing Republicans’ complaints about fairness as hypocritical, given that Mr. Trump has blocked witnesses and documents at every turn.
“You have to give them credit for nerve, if nothing else,” said Representative Adam B. Schiff, Democrat of California and the chairman of the Intelligence Committee.
Ms. Pelosi and other Democrats leading the inquiry note that they have repeatedly invited Mr. Trump to produce exculpatory evidence or present a defense, and he has done neither. Republicans, they argue, are trying to pervert the concept of fairness to disrupt and delay the inquiry, not to meaningfully participate in the process.
The speaker could walk on water to be fair, and Republicans would still “criticize her for not being able to swim,” said Representative Hakeem Jeffries of New York, the chairman of the Democratic caucus and an ally of Ms. Pelosi’s.
Neal Katyal, the former acting solicitor general under President Barack Obama, called it “deeply dangerous” for the target of an impeachment like Mr. Trump to simply boycott the entire process.
“The fact is that the House Democrats are essentially giving Trump the same process as previous presidents have received, and it’s Trump who is trying to throw out the rule book” and attack the process at every turn, he said. “Our founders put impeachment in the Constitution as a critical safeguard for the people, and what Trump is trying to do with these baseless attacks is read the impeachment clauses out of the Constitution.”
Angry that no one is defending his actions the way he believes they should, Mr. Trump periodically asks aides whether he should send witnesses to comply with congressional subpoenas. But that impulse then fades, as the president becomes convinced that such a move would not end the inquiry.
Mr. Trump and his close circle of advisers are convinced that the Ukraine inquiry is merely an extension of the investigation into Russian election meddling and the continuation of a three-year assault on his presidency that began the day he was inaugurated with the launch of an activist’s website, ImpeachDonaldTrumpNow.org.
His response has been an all-out attack on the process itself. He has ordered administration officials not to testify or hand over documents. And he is urging Republicans not to cooperate with their counterparts the way they did during Mr. Clinton’s impeachment.
Mr. McNulty said that dynamic had the potential to damage the nation’s politics for years, and could permanently alter the intent of the authors of the Constitution.
“It’s going to break everything in half,” Mr. McNulty said. “My hope would be, as a citizen, that when this is over, somehow, some way, we could stop and think about what impeachment was meant to be for.”
Catie Edmondson and Emily Cochrane contributed reporting.