Barely two years ago, Democrats were dreaming of bringing statehood to D.C. Now they’re fighting a historic challenge by Republicans to the city’s self-governance.

And the resulting clash might force Joe Biden to issue his first veto as president.

It all started when the House GOP took aim last week at a package of progressive criminal justice measures approved by the D.C. council in November. Thirty-one Democrats joined with Republicans to oppose the new D.C. bill. Now, Senate Republicans are poised to force a vote next month on sending that D.C. criminal justice rollback to Biden’s desk. And, in a twist, D.C. Mayor Muriel Bowser, a critic of her city council’s work, vetoed the bill last month and is not lobbying against efforts to overturn it.

With all 49 Republicans already in favor and many Democrats still undecided, Biden’s party is highly alarmed that the disapproval resolution could pass. That outcome would spotlight the party’s divide over the issues of crime and D.C. self-governance.

“I have concerns about passage here. Of course, the president could veto. He’s going to have to make that decision,” said Sen. Chris Van Hollen (D-Md.). “Congress shouldn’t be bigfooting decisions made by the elected representatives of the people of the District. I will be talking with [Democrats] about this general principle.”

Biden has come out in opposition to the legislation but not made an explicit veto threat. Democratic leaders believe he is prepared to do so: “I’d assume, but I wouldn’t go any further,” said Senate Majority Whip Dick Durbin (D-Ill.), who chairs the Judiciary Committee.

The reversal of D.C.’s crime law cannot be filibustered, and if 51 senators vote yes it would be the first time since 1991 that Congress has rolled back a statute in the capital city. It’s a stunning turnaround from last Congress, when 46 senators in the Democratic Caucus went on record to support making D.C. a state while the Democratic House passed its own statehood bill.

Rep. Angie Craig speaks at a press conference outside the U.S. Capitol.