Republican leaders plan to sue Speaker Nancy Pelosi and top congressional officials on Tuesday to block the House of Representatives from using a proxy voting system set up by Democrats to allow for remote legislating during the coronavirus pandemic, calling it unconstitutional, according to three officials familiar with the case.
In a lawsuit that will name Ms. Pelosi, as well as the House clerk and sergeant-at-arms, as defendants, Representative Kevin McCarthy of California, the minority leader, and roughly 20 other Republicans planned to argue that new rules allowing lawmakers to vote from afar during the coronavirus outbreak would be the end of Congress as it was envisioned by the nation’s founders.
Democrats pushed through the plan this month over unanimous Republican opposition.
The Republicans planned to ask a federal judge in Washington to strike down the practice immediately — leaving uncertain the fate of legislation the House plans to take up this week using the new procedures — and to invalidate it permanently. The officials who described the suit did so on the condition of anonymity before its filing in a federal court in Washington.
The suit will face an uphill battle in the federal courts, where judges have been reluctant to second-guess Congress’s ability to set its own rules. But it would fit into a broader push by Republicans, led by President Trump, to put a cloud of suspicion over Democratic efforts to find alternative ways to vote during the pandemic — both in the House and in elections across the country — portraying them as fraudulent attempts to gain political advantage.
Mr. Trump has railed repeatedly in recent weeks against the idea of expanding mail-in voting, and on Tuesday said a plan to allow for the practice in California would lead to a “Rigged Election.”
“No way!” the president wrote on Twitter.
On Sunday, the Republican Party sued Gov. Gavin Newsom and the state’s secretary of state in an attempt to strike down an executive order dispatching mail-in ballots to every registered voter there, deriding it as an “illegal power grab” and part of Democrats’ “partisan election agenda.”
Mr. McCarthy has also called the House’s new voting procedures a “power grab” by Democrats.
On Thursday, Senator Mitch McConnell, Republican of Kentucky and the majority leader, tied the two issues together, saying the House Democrats’ proxy voting plan came from “the people who want to remake every state’s election laws.” He also suggested that his chamber might not take up any legislation passed by the House when a quorum of members was not physically present.
“There will be enormous constitutional questions around anything the House does if they fail to demonstrate a real quorum but plow ahead anyhow,” he said.
The new procedures adopted by the House allow any absent lawmaker to designate another member who is physically present to record a vote on his or her behalf, during periods when the speaker, the clerk and the sergeant-at-arms agree there is a state of emergency because of the coronavirus.
Democratic leaders insist that the update to the House rules is a good-faith attempt to put a vital branch of government back to work safely on an emergency basis.
Still, Democratic leaders who planned to deploy proxy voting for the first time as soon as Wednesday must now decide whether to reconsider or risk a legal decision ultimately invalidating the bills they pass using remote votes. House leaders have already collected letters from at least 50 lawmakers, all Democrats, indicating they may use a proxy to cast their vote on the bill from home.
Along with Ms. Pelosi, the suit is expected to name Cheryl L. Johnson, the clerk of the House, and Paul D. Irving, the sergeant-at-arms. Ms. Johnson and Mr. Irving are not in any way responsible for the rules changes, but they do play a key role in carrying them out.
Senate Republicans also view Democrats’ argument for proxy voting as constitutionally suspect and appear to be weighing their own challenge to the rules change.
Mr. McConnell has rejected a bipartisan bid to institute remote voting, and has brought the Senate back to work in person.
Democrats and the constitutional scholars they consulted in drafting the changes take the opposite view, arguing that the Constitution clearly empowers the House and the Senate to set their own rules, and that for two centuries the House has adapted to better function in its times. Just because earlier generations with primitive technologies at their disposal did not consider remote voting does not mean the House today should not, they argue.
Democrats have also already rejected Republicans’ claim that proxy voting dilutes the voices of members of Congress and the people they represent by allowing a single lawmaker to vote for others. On the contrary, they assert, under the present circumstances it actually makes the body more representative.
“We believe proxy voting is not only consistent with the Constitution but consistent with the responsibility a member has to express the views of their constituents, whether or not they can get to Washington, D.C.,” said Representative Steny H. Hoyer, Democrat of Maryland and the majority leader.
It is far from assured that a court would weigh in on the issue. Republicans would first have to convince a judge that they have standing to sue, and if they were unsuccessful, the case could get tossed out without any consideration of its merits.
Legal scholars discussing proxy voting in the past have said the courts may be especially reluctant to question Congress’s ability to set its own rules at a time when the courts themselves are taking similar steps to move their proceedings online.
Mr. McCarthy and two top deputies spent weeks this spring negotiating with Democrats about possible ways to get Congress back to work, including remotely. Republicans indicated they were comfortable with remote committee hearings, but drew a line at allowing members to vote remotely either by proxy or using digital technology, changes they argued were not only constitutionally dubious but would alter the fabric of the institution in lasting ways.
The conservative constitutional lawyer Charles Cooper is bringing the suit on behalf of the House Republicans. It will be the second time in the past year that Mr. Cooper has filed a lawsuit related to a controversial congressional matter. During impeachment proceedings, he filed a suit that ultimately led to John R. Bolton, the former national security adviser, not testifying against the president.
Emily Cochrane contributed reporting.