Senate Democrats launched their effort to pass sweeping voting rights legislation Wednesday, which could become the centerpiece of an attempt to weaken the chamber’s filibuster rule.

Majority Leader Chuck Schumer said proposals to roll back voting access in numerous Republican-led states this year represent a threat to democracy that would be countered by the legislation, which closely parallels a measure already passed by the House.

“We are standing up to the despicable, despicable acts of voter suppression in so many states,” Schumer said at a news conference. He said proposals in GOP states “smack of Jim Crow” laws designed to restrict Black voters.

The legislation is broadly opposed by Republicans, who are likely to attempt to block it in the Senate through a filibuster, which requires 60 votes to overcome. That may make the bill a test case for efforts among some Democrats to do away with or revamp the century-old rule that allows the minority party to prevent votes.

Some Democrats, notably West Virginia Senator Joe Manchin, have said they oppose jettisoning the filibuster entirely. But Manchin recently said he might support making the filibuster more “painful” to employ, such as requiring a senator to stay on the floor and talk to delay a vote, a tactic made famous Jimmy Stewart in the 1939 film “Mr. Smith Goes to Washington.”

President Joe Biden, a former senator, also has endorsed that approach.