A Missouri court has upheld a mid-decade redistricting plan that gives Republicans a chance to win an additional congressional seat in this year’s midterm elections.

The Missouri Supreme Court on Tuesday upheld a mid-decade redistricting plan that gives Republicans an improved chance at winning an additional U.S. House seat in this year’s midterm elections.

The decision marks a legal victory for Donald Trump in a nationwide redistricting battle. But it may not be the final word. Opponents have submitted more than 300,000 petition signatures in an attempt to put the new map to a statewide vote.

Missouri’s Republican-led Legislature approved new U.S. House districts in September at the urging of Trump, shortly after Texas Republicans also redrew their congressional districts. Trump is hoping the new districts could help the GOP hold on to its narrow majority in the House, where Democrats need to gain only a few sets in November to win control and impede Trump’s agenda.