The state of voting rights in America was already dire before Justice Anthony Kennedy announced his retirement on Wednesday. His departure from the bench ensures that voter suppression—and, specifically, partisan gerrymandering—will get much, much worse. In Kennedy’s absence, there is virtually no chance that the court will put constitutional limits on political redistricting. There is, however, a decent probability that the court will strike down reforms to partisan gerrymandering, sharply limiting citizens’ ability to curb legislative abuse of the redistricting process. The upshot will be fewer competitive elections and greater entrenchment of one political party, usually the GOP, in most states.

Partisan gerrymandering occurs when mapmakers tasked with drawing legislative districts manipulate the lines to favor one party over the other. Both parties do it, but Republicans are significantly better at it, partly because they funneled money into high-tech gerrymandering after the 2010 election. In the Wisconsin statehouse, for instance, Republicans have maintained a huge majority despite the state’s balanced political landscape; in 2012, the GOP won 48.6 percent of the statewide vote, but seized 60 out of 99 seats in the state assembly. That outcome is directly attributable to Republicans’ gerrymander.

Voting rights advocates challenged Wisconsin’s map at the Supreme Court, urging the justices to restrict mapmakers’ ability to dilute citizens’ votes on the basis of their political affiliations. But the court punted the case, likely because Kennedy couldn’t make up his mind. With the swing justice gone, there is simply no chance of the court invalidating gerrymandered maps.

To the contrary, Kennedy’s replacement may actually allow the court to strike down state-level efforts to restrain congressional gerrymandering by stripping legislators of their redistricting powers. In 2015, the Supreme Court upheld Arizona’s independent redistricting commission, which voters approved through a ballot initiative. It did so by a 5–4 vote, with Kennedy joining the liberals to hold that the citizens of a state may exercise “the legislative power” by removing redistricting from legislators’ hands.

In response, Chief Justice John Roberts wrote a seething dissent joined by the other conservatives. “The Court’s position,” he wrote, “has no basis in the text, structure, or history of the Constitution.” Roberts insisted that the Arizona commission violated the Constitution’s Elections Clause, which states that the “Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof.” To Roberts, redistricting is part of the “manner of holding elections,” and so it must be “prescribed” by the legislature, not an independent commission.

Depending on how broadly the court rules, it could put other progressive electoral reforms on the chopping block as well.

Roberts’ dissent in the Arizona redistricting case was one of the angriest of his career, and he left little doubt that he would revisit and reverse the holding if given the opportunity. He may soon have one. In November, Michigan residents will vote on a ballot initiative that would create an independent redistricting commission similar to Arizona’s. The reform is long overdue, as Michigan’s districts are badly gerrymandered. In the 2016 election, Republicans and Democrats received roughly the same number of votes statewide, yet Democrats won just five seats in the House of Representatives while Republicans won nine. That gerrymander remains in place for the 2018 election, which could help Republicans retain a majority in the House even if they lose the popular vote.

If voters approve the independent redistricting commission, Republican state legislators are almost certain to challenge it in court. And if their lawsuit reaches the Supreme Court, Roberts will have the opportunity to turn his 2015 dissent into law. In the process, he could strike down not only Arizona’s commission, but also California’s, which similarly removes legislators from the business of redistricting.

Depending on how broadly the court rules, it could put other progressive electoral reforms on the chopping block as well. If the U.S. Constitution gives state legislatures near-absolute control over redistricting, then bipartisan commissions could also be doomed. Legislators typically appoint members of both parties to these boards, then cede redistricting duties to their picks. That process certainly doesn’t comply with Roberts’ literal reading of the Elections Clause, which requires legislators themselves to draw the maps. Five states currently use bipartisan commissions to draw congressional districts, and more could join them soon. Kennedy’s successor could provide the fifth vote to wipe out their work.

But why stop there? Plenty of other states impose limits on the legislature’s ability to gerrymander. For example, 13 state constitutions require elections to be “free and equal,” while a Florida constitutional amendment expressly mandates fair districts. State supreme courts, most notably Pennsylvania’s, have used these provisions to strike down partisan gerrymanders and, when necessary, draw remedial congressional maps. The U.S. Supreme Court refused to hear a last-minute challenge to the Pennsylvania Supreme Court’s map, possibly because the conservatives believed Kennedy would vote to approve it. In his absence, they could bar state courts from redrawing congressional districts to remedy partisan gerrymanders. After all, a court is not a “legislature,” and according to Roberts, only state legislatures have constitutional authority over redistricting.

Kennedy was never a consistent supporter of voting rights. And in the end, he lacked the nerve to rein in legislators who had taken political redistricting to new extremes. But he also resisted efforts to block citizens from addressing the problem through the democratic process. His successor will probably lack that deferential impulse. The result may be catastrophic for the decadeslong bipartisan effort to combat partisan gerrymandering.