On Monday, Justice Samuel Alito rejected Pennsylvania Republicans’ last-ditch effort to preserve the partisan gerrymander of their state’s congressional map. The justice’s decision effectively ensures that Pennsylvania’s 2018 congressional elections will be held under a much fairer map, giving Democrats an opportunity to win several more seats in the state. In fact, the dissolution of Pennsylvania’s gerrymander gives Democrats a significantly better shot at winning control of the House of Representatives in November.

SCOTUS intervention in the Pennsylvania redistricting litigation was always unlikely. When the Pennsylvania Supreme Court invalidated the current map on Jan. 22, it did so exclusively under the Pennsylvania Constitution. The U.S. Supreme Court cannot overrule a state supreme court on a question of state law; it may only step in when a state law or court order violates the federal Constitution. Republican legislative leaders had argued that the Pennsylvania Supreme Court’s decision ran afoul of the federal Constitution’s Elections Clause, which allows state legislatures to prescribe “the times, places and manner of holding [congressional] elections.” Legislators asserted that their state Supreme Court had unlawfully stripped them of their constitutional prerogative to draw congressional maps.

But this argument is plainly untenable for two reasons. First, the U.S. Supreme Court held in 2015 that the Elections Clause does not grant state legislatures exclusive redistricting power. Indeed, the court found that citizens could prohibit their state legislature from redistricting altogether and direct an independent commission to draw congressional maps instead. If a legislature can be deprived of all redistricting power, surely it can also be compelled to draw districts that comport with the state constitution.

Second, the GOP legislators’ position would bar courts from reviewing the legality of any congressional gerrymander. Under their argument, no court could strike down a gerrymander, partisan or otherwise, or draw remedial maps to remedy constitutional flaws. Courts are not legislatures, after all, so judges would have no authority to intercede in gerrymandering disputes. No justice, not even Clarence Thomas, has ever held that legislative redistricting is insulated from judicial review.

Alito’s dismissal of Pennsylvania Republicans’ appeal, then, was pretty much inevitable—although the justice appears to have given it more consideration than it deserved. (Alito reviews emergency appeals out of Pennsylvania; he dismissed this appeal without referring it to the full court, though he did order a response from voting rights advocates.) Monday’s decision was also excellent news for Democrats, who were hobbled by the GOP-drawn map. Registered Democrats significantly outnumber registered Republicans in Pennsylvania, yet Republicans won 13 out of 18 congressional districts in 2016. The Associated Press found that the gerrymander likely gave Republicans at least three extra House seats.

Monday’s dismissal is especially bad news for one Republican in particular: Pennsylvania Senate President pro tempore Joseph Scarnati. Last Wednesday, Scarnati declared that he would defy a Pennsylvania Supreme Court order requesting data to help it commission a nonpartisan map. The legislator insisted that SCOTUS would soon reverse the state Supreme Court. Now that it has refused to do so, Scarnati is out of options: He must turn over the data or risk being held in contempt of court. Pennsylvania’s midterm elections will be held in much fairer districts, whether Republicans like it or not.