ap photo House Speaker Nancy Pelosi of Calif., speaks during a news conference on Capitol Hill, Wednesday in Washington.

WASHINGTON — It was a day for the history books on Capitol Hill: For the first time, House lawmakers voted by proxy, an unprecedented move to avoid the risks of travel to Washington during the pandemic.

To mark Wednesday’s history-making moment, House Republicans sued to stop the Democratic majority’s new system, in which absent lawmakers can instruct those present to vote on their behalf.

The House rules change tries to strike a balance between working from home during the coronavirus outbreak and honoring the Constitution’s requirement to be “present” and voting. But it’s fast becoming a political test on party lines. More than 70 Democrats cast their vote by proxy. Twenty Republicans joined the lawsuit against the move, which House GOP leader Kevin McCarthy of California says is unconstitutional.

“It’s a dereliction of duty,” McCarthy said.

The House returned to Washington for an abbreviated two-day session as the city remains under stay home orders. The much smaller Senate is on recess after spending much of May in the capital.

Deadlocked over the next big coronavirus relief bill, Congress is shifting its attention to a more modest overhaul of small-business aid in hopes of helping employers reopen shops and survive the pandemic.

But the agenda is in flux. There were no formal talks between congressional leaders on the next phase of the federal coronavirus response. Democrats have pushed a $3 trillion-plus measure through the House, but negotiations with the GOP-controlled Senate and White House have yet to begin.

“We can’t keep propping up the economy forever,” Senate Majority Leader Mitch McConnell said Tuesday in Lexington, Kentucky. “The ultimate solution is to begin to get back to normal.”

The day showcased the new proxy system. Republicans declined to participate, but dozens of Democrats — many from California and other Western states — submitted formal requests for proxy votes to the House Clerk.

Democrats engineered the rules change, approved earlier this month, that allows a lawmaker to formally ask a colleague to vote on his or her behalf. A single lawmaker can carry 10 votes.

One by one, as voting was underway on the first bill, the Uighur Human Rights Policy Act of 2020, some 40 lawmakers rose to announce the proxy votes they represented. They stated each colleague’s name and the person’s intended vote, and the actions were recorded. Some lawmakers represented up to 10 representatives, though most carried votes from just one or two.

Not even during the Civil War, the Spanish Flu or any other emergency has the House allowed proxy floor votes.