Pennsylvania Lt. Gov. John Fetterman, a leading Democratic contender in the state’s Senate race, went after Sen. Joe Manchin (D-W.Va.), saying it was “naive” of him to think Republicans will cooperate with Democrats in Congress.

Fetterman specifically targeted Manchin over his opposition to the For the People Act, a sprawling voting rights bill that has the support of the remaining 49 Democrats in the Senate. Manchin said he opposes it because it lacks bipartisan support. 

“Democratic Sen. Joe Manchin is wrong to choose to vote against the For the People Act, a bill that would increase election security and access to voting and reduce the influence of big money in politics. To pretend that former President Donald Trump’s Republican Party will act in good faith to preserve democracy is naive,” Fetterman wrote in a CNN op-ed. 

“If I were in the Senate now, my ‘yes’ vote on the For the People Act would not be about my party. It would not be about politics. This is about doing what I know is right, guaranteeing that everyone has the right to vote,” he wrote.

The For the People Act would requires states to offer mail-in ballots and a minimum of 15 days of early voting, while calling for online and same-day voter registration, among other top reforms that Democrats say would expand access to the voting booth.

Fetterman has been a vocal proponent of the voting rights bill and abolishing the Senate filibuster, putting him at odds with Manchin on two top issues for Senate Democrats.

However, he has rarely gone after the West Virginia centrist in such blatant terms.

Manchin’s office did not immediately respond to a request for comment from The Hill. 

Fetterman is running in one of the Senate’s most closely watched Senate races. The Pennsylvania contest to replace outgoing Sen. Pat Toomey (R) is a linchpin of both parties’ strategies to winning the majority in the upper chamber in the next Congress.

Fetterman has cast himself as a staunch progressive in the race but has vowed to be a team player should he be elected to the Senate.