A House bill to establish a bipartisan commission to investigate allegations of Russian interference in last year’s presidential election has garnered its first Republican supporter.

Rep. Walter B. Jones (R-N.C.) co-sponsored the Protecting Our Democracy Act on Thursday, a spokeswoman for Jones confirmed Friday. He joins every member of the House Democratic Caucus in co-sponsoring the bill, which would set up a 12-member panel evenly divided between Republicans and Democrats.

The bill, introduced by Reps. Eric Swalwell (D-Calif.) and Elijah E. Cummings (D-Md.), gives the commission powers to investigate “any attempts or activities by the Russian government, persons or entities associated with the Russian government, or persons or entities within Russia to use electronic means to influence, interfere with, or sow distrust in elections for public office held in the United States in 2016.”

The spokeswoman for Jones, Allison Tucker, said the congressman had no further comment on why he joined the bill.

Jones has previously broken with his party on matters of national security and defense: He was among the very first elected Republicans to turn against the Iraq War and express regret for his vote to authorize military force based on faulty intelligence wielded by President George W. Bush’s administration.

A pair of Republican senators — Lindsey O. Graham of South Carolina and John McCain of Arizona — backed a bipartisan probe of Russian interference in the election, but they stopped short of calling for the sort of appointed commission that Swalwell and Cummings have proposed. Republicans in both the House and Senate are now largely supportive of having the intelligence communities in each chamber investigate the matter.

But Swalwell, a member of the House Permanent Select Committee on Intelligence, said Thursday that he had approached numerous House Republicans about joining the bill. Many, he said, expressed agreement with its aims but said they were wary of supporting the Democratic measure for political reasons.

With Jones, “The dam has cracked,” Swalwell said. “This is the first time any of them have done anything on Russia with us. … The Republicans who have been on the sidelines wanting to get on the field, but a little nervous, they don’t have to be the first Republican. There’s a Republican on board.”

“Our hope is, the first one has come, now you don’t have to be the first one,” he continued. “You can get on board.”

Cummings, the ranking Democrat on the House Oversight and Government Reform Committee, made a similar point Thursday: “Hopefully this will break open something. We don’t know.”

Karoun Demirjian contributed to this report.