Coronavirus Is in the Capitol. Some Lawmakers Think They Shouldn’t Be.

WASHINGTON — Under pressure to upend centuries of tradition to respond to a growing pandemic, congressional leaders reluctantly agreed on Thursday to at least study the feasibility of allowing lawmakers to vote from home, after two House members tested positive for the coronavirus and a dozen others were quarantined.

Speaker Nancy Pelosi, who was staunchly opposed to the idea last week, told House Democrats during a private conference call on Thursday that she had asked the chairman of the Rules Committee, Representative Jim McGovern of Massachusetts, to prepare a report on remote voting and other relevant issues, according to three officials who heard it.

Democratic leaders were also looking at other, less drastic means to limit the number of the House’s 430 members on the floor at a given time, and one raised the possibility that the House could try to move without a vote to adopt a $1 trillion coronavirus rescue bill being negotiated with the White House. Such action, known as a “unanimous consent” request, is normally reserved for the most minor and uncontroversial of bills — not huge and complex pieces of legislation responding to a global crisis.

The reconsideration of the matter came as support was swelling in both parties for the House to amend its rules to allow lawmakers to vote remotely for the first time as long as travel and social restrictions are in place to combat the spread of the virus. A parallel attempt in the tradition-bound Senate was unlikely to persuade Republican leaders there.

The issue became more urgent late Wednesday, after Representatives Mario Diaz-Balart, Republican of Florida, and Ben McAdams, Democrat of Utah, disclosed that they had fallen ill after voting on the House floor early Saturday, and later tested positive for the virus. Between them, the two could have transmitted the virus to colleagues, many of whom are older. Congress’s attending physician was called in to trace their contacts.

“In. Person. Voting. Should. Be. Reconsidered,” Representative Debbie Mucarsel-Powell, Democrat of Florida, wrote on Twitter late Wednesday. “For the safety of our communities, during this emergency, we must be able to legislate from our districts.”

Congress has eschewed its usual voting rules before in times of national emergency, using unanimous consent, for instance, to enact urgent health relief measures to fight the Spanish influenza in the fall of 1918 when many members were either sick or scattered across the country. But the House and Senate have never allowed a member to cast a recorded vote from anywhere but inside their chambers, and any changes could be challenged on legal grounds.

It is that tradition that Ms. Pelosi and other senior lawmakers, many of them in their 70s and 80s, had in mind as they have forcefully shut down talk of voting from afar even as public health officials warned that their demographic was the most at risk.

Instead, they have suggested limiting the number of members on the floor, among other precautions.

Proponents of the changes argued they could be the best way to set an example for millions of constituents around the country who are being told not to travel or congregate in groups larger than 10, as well as to provide continuity at a time when more lawmakers are likely to grow sick or unable to travel.

Almost 150 members of the House and nearly half of senators are 65 or older, the very group the Centers for Disease Control and Prevention is advising not to travel or convene in large groups.

Ms. Mucarsel-Powell was among more than 50 House members — almost all Democrats — who signed a letter Wednesday to Ms. Pelosi and the top Republican, Representative Kevin McCarthy of California, urging them to authorize remote voting “as necessary.”

“We write to ask that the House of Representatives hold itself to the same high standard that it is asking of the nation: to put public health and safety first,” they wrote in the letter, sent before their two colleagues reported having tested positive. “While Congress is an institution with a proud history, we cannot stand on tradition if it puts lives — and our ability to be the voice of our constituents — at risk.”

The leaders appeared to be listening.

On Thursday, Representative Steny H. Hoyer, Democrat of Maryland and the majority leader, announced that the House would not return from its current recess until it was ready to vote on its third emergency relief bill. And later, on the conference call, he told Democrats they could try to pass that legislation without a vote, though it would be difficult since any single member could object.

Both chambers have already sought to limit risks, sending staff home and replacing in-person meetings and town halls with conference calls or video chats.

But voting, the most symbolically weighty act any elected official can take, has been another matter, even if the idea of hundreds of House members and 100 senators gathering on crowded chamber floors is an epidemiological nightmare.

“When we’re in there talking and having those conversations, we make bills better,” Representative Mark Green, Republican of Tennessee and an emergency room doctor, said in explaining why he was no fan of remote voting. Better just to limit the number of lawmakers grouped together at once, he said.

The cases of Mr. Diaz Balart and Mr. McAdams clearly illustrated the risk, as their illnesses sent ripples through the House. Both men were on the House floor voting as recently as last Saturday, as Congress worked into the early hours of the morning to pass a coronavirus relief bill including free testing for all Americans.

At least a dozen members who had met in person or in small groups with the two men announced one by one that they would protectively self-quarantine, including the second-ranking Republican, Representative Steve Scalise of Louisiana.

Brian P. Monahan, Congress’s attending physician, told lawmakers that his office had identified individuals and locations in the Capitol that could have been affected and was advising them. He said other members who may have encountered the men on the House floor were likely fine.

Representative Eric Swalwell, Democrat of California, who has been pushing for remote voting since 2013, argues that it could be accomplished relatively simply: Lawmakers could connect via video chat with a House clerk and record their votes on a given issue. Other steps could be taken to verify their identities.

Prospects appeared narrower in the Senate.

Two senior senators, Rob Portman, Republican of Ohio, and Richard J. Durbin of Illinois, the second-ranking Democrat, introduced a bill on Thursday that would allow the two party leaders to jointly permit remote voting in times of “extraordinary national crisis.”

“I go out and I touch 5,000 people a week — that’s probably conservative — and then come back here and talk with people who have touched 5,000 people a week,” said Senator Jon Tester, Democrat of Montana. “Exactly the opposite of what the C.D.C. is recommending.”

But Senator Mitch McConnell, Republican of Kentucky and the majority leader, flatly rejected the idea of remote voting in the Senate this week, telling reporters on Tuesday, “We’ll not be doing that.”

His position has the support of some of Congress’s older members, who are firmly against breaking with tradition, regardless of warnings from their younger colleagues.

“Showing up is part of the vote,” said Senator Dianne Feinstein, 86, Democrat of California, before playing down the threat compared with the killings of two San Francisco officials she witnessed in the early days of her political career. “I’ve been in worse situations, I’ve seen people shot and killed, I’ve found dead people, all of that. So this is not a big deal.”

Emily Cochrane and Sheryl Gay Stolberg contributed reporting.