WASHINGTON — A key House panel was set to begin the formal debate Wednesday evening over two articles of impeachment against President Trump, taking the Democratic-led House’s first steps toward formally charging him with abuse of power and obstruction of Congress.
The House Judiciary Committee planned to convene at 7 p.m. Eastern to start what will probably be a two-day meeting that is expected to culminate on Thursday with approval of the articles, along party lines, which will send them to the full House. The rare evening session will give each of the 41 members of the committee a chance to argue for or against Mr. Trump’s impeachment. It could go late into the night.
Leaning with equal weight on the Constitution and the findings of their two-and-a-half-month inquiry, Democrats plan to make an impassioned case that Mr. Trump put the 2020 election and the nation’s security at risk by using his office to pressure Ukraine to investigate his political rivals, and then trampled on the Constitution and the separation of powers by seeking to conceal his actions from Congress.
“We will see an articulation of the values driving both impeachment and the opposition to it,” said Representative Jamie Raskin, Democrat of Maryland and a member of the Judiciary Committee.
Republicans will argue that the case is overstated, insufficiently proven and the product of a desperate attempt by Democrats to remove a president they do not like. No lawmaker on the notoriously partisan and raucous panel is expected to cross party lines.
“A pointless oratory contest,” Representative Matt Gaetz, Republican of Florida, a member of the committee, said before the gathering.
The dueling statements are likely to stretch into the night before Representative Jerrold Nadler, Democrat of New York and the chairman of the committee, is expected to call a recess. Then on Thursday morning, Mr. Nadler plans to reconvene the panel to begin the protracted process of proposing edits and amendments to the two articles themselves. By that afternoon, the panel is expected to vote along party lines to approve the articles and recommend them to the full House, which is likely to take swift action.
House Democratic leaders are eyeing a final vote as early as Tuesday to impeach Mr. Trump.
Republicans may use the meeting on Wednesday — called a “markup” because it is a chance for lawmakers to edit the impeachment articles — as a chance to try to water down the charges with amendments. Progressive Democrats could try to insert tougher language or even add additional charges. But any changes are subject to a vote of the committee, which is skewed heavily in favor of Democrats, and Mr. Nadler expects few, if any, of his own members to try to change what were carefully worded texts.
With the outcome in the Judiciary Committee all but certain, Democratic leaders were also looking ahead on Wednesday to the final debate and impeachment vote on the House floor next week. Mr. Nadler was expected to meet with Speaker Nancy Pelosi and Representative Jim McGovern, Democrat of Massachusetts and the chairman of the Rules Committee, Wednesday afternoon to try to pin down a date for the final vote.
Those leaders are confident they have the votes to pass both articles. Some moderate Democratic lawmakers, uneasy with the prospect of a partisan impeachment, have held private discussions this week about trying to build bipartisan support to censure Mr. Trump instead. But time is running short, Republicans have shown no sign they would be willing to break with the president, and the Democrats concede an 11th hour change is unrealistic.
In the Senate, where the parties’ respective leaders ticked through their year-end to-do list on Wednesday, the prospect of hosting an impeachment trial when they return from the year-end break was weighing heavily on their thinking.
Senator Mitch McConnell, Republican of Kentucky and the majority leader, chastised the House for what he called “the least thorough and most unfair impeachment inquiry in modern history.”
“The House Democrats’ denigration of their solemn duty will not cause the Senate to denigrate ours,” Mr. McConnell said on the Senate floor. “If the House continues down this destructive road and sends us articles of impeachment, the Senate will take them up in the new year and proceed to a fair trial.”
His Democratic counterpart, Senator Chuck Schumer of New York, had a different warning. He urged the president to provide evidence he withheld from House investigators and make government officials who could shed further light on the events in question available for questioning.
“The House has made an extremely strong case,” Mr. Schumer said. “The burden now lies on the president to rebut it if he can.”
The articles of impeachment include two counts against Mr. Trump and run for nine pages that were carefully crafted by lawyers for the Judiciary and Intelligence Committees in recent days.
Thursday’s session will begin with a committee clerk reading the articles aloud.
The first article, abuse of power, accused Mr. Trump of “using the powers of his high office” to solicit foreign assistance from Ukraine in the 2020 election. Specifically, it asserts that Mr. Trump withheld $391 million in military aid and a coveted White House meeting for Ukraine’s president as leverage for extracting public announcements of investigations into former Vice President Joseph R. Biden Jr. and his son, as well as an unsubstantiated theory that Ukraine conspired with Democrats to swing the 2016 election against Mr. Trump.
The second article, obstruction of Congress, charges that by systematically blocking administration officials from speaking to House investigators and refusing to comply with any subpoena for relevant records, Mr. Trump demonstrated unprecedented “defiance of an impeachment inquiry” and sought to cover up his own wrongdoing.