The Supreme Court sided with opponents of a Republican-friendly congressional map in Missouri on Thursday, handing down a quick decision rejecting a plan that could have given the GOP an extra seat in the House of Representatives.

The order, issued without explanation and no noted dissent, will almost certainly mean the state will use a previous map that included six – rather than seven – winnable seats for the GOP.

The brief decision will likely affect only a single seat, however, it is an unusual election-related loss for Republicans at the 6-3 conservative Supreme Court. And it undercuts President Donald Trump’s effort to eke an advantage out of state congressional maps across the country to retain Republican control of the House next year.