The death of U.S. Supreme Court Justice Antonin Scalia on Saturday sets up a battle between the White House and the Senate over who will nominate a new associate justice—a dispute over governing norms and constitutional imperatives, played out in the most powerful republic in the world.

The outcome of that fight could also exert unusual influence over the health of the planet and the survival of its natural systems. For although Scalia’s death has already changed the outlook for a number of cases now in front of the Supreme Court, it will also alter the shape of one that will soon arrive: the legal battle over the Clean Power Plan.

The Clean Power Plan is the new set of Environmental Protection Agency regulations that anchors the Obama administration’s climate-change policy. It seeks to guide local utilities away from coal-fired electricity generation, and toward renewable energy and natural gas, a change that the Department of Energy says will forestall hundreds of millions of tons of greenhouse-gas emissions. The plan’s survival—and its entry into law—could decide the fate of the Paris Agreement, the first international treaty to mitigate climate change. For a case that will ultimately turn on administrative law, it’s hard to imagine the stakes being much higher.

It had already been a busy week for the Clean Power Plan. On Tuesday, the Supreme Court ruled 5-4 that the rules should neither be implemented nor enforced until the high court itself heard their opponents’ case. This was itself unprecedented: Never before had the Supreme Court stayed a set of regulations before a federal court even heard the initial case about them.

This was an ominous sign for the regulations. “One has to conclude that five justices have decided that the rule must go,” said Seth Jaffe, the former president of the American College of Environmental Lawyers.

But Scalia’s death could change all that. Now there are only four justices who have telegraphed their opposition to the rules. Could the Clean Power Plan now survive, after all?

There are two questions to ask when gaming out the future of this particular case. First, would the Court revisit its stay on the rule, allowing the EPA to proceed to implement the regulations? And second, if the Court does hear the case about the Clean Power Plan, could its new membership change its decision?

As to the first, no legal expert I talked to thought the now-smaller Court was likely to annul its stay.

“There is currently no reason to assume the Court will revisit the stay order,” said Richard Lazarus, an environmental-law professor at Harvard University and a veteran of oral arguments at the Court, in an email. “It is final as voted on by the full Court at the time and is not subject to revisiting any more than any other ruling by the Court before the Justice’s passing.”

The second question is more complicated. The terms of the Court’s stay were broad: It ordered that the Clean Power Plan could only enter into force after the Court itself ruled; or if the D.C. Circuit Court of Appeals heard its case (as it is scheduled to do this summer) and the Supreme Court declined to hear the inevitable appeal.

In the language of the Court, taking up a case is “granting a writ of certiorari,” often shortened to “granting cert.” Unlike in a decision on a case, in which five justices determine how the court rules, only four justices need to vote to grant cert in a case. Most experts thought it was likely that the Court—whatever its makeup—would eventually hear the case.

Then things get more complicated.

“The Senate Republicans have already made it clear that they will not confirm anyone President Obama nominates. So it could fall to the next President to name the next justice.  And that makes even higher the stakes in the next presidential election,” said Michael Gerrard, a law professor at Columbia University and the director of the Sabin Center for Climate Change Law, in an email.

“If no Obama appointee is confirmed, and if Hillary Clinton or Bernie Sanders is the next President, the next Justice will presumably join the liberal wing of the court, and there is a good chance that he or she would vote to uphold the Clean Power Plan,” he told me. “That of course assumes that nominee gets confirmed before the case is decided; this could well be a massive and protracted confirmation battle, given the high stakes for so many areas of law.”

If a Republican wins the White House, their Supreme Court nominee would almost certainly join the Supreme Court’s conservative wing. That justice would be unlikely to vote to support the Clean Power Plan—but it wouldn’t matter, because no remaining Republican candidate supports Obama’s climate policies, anyway, so they’d likely be reversed administratively.

There’s some possibility that the Supreme Court could hear the Clean Power Plan case before a ninth justice is appointed. If it then split 4-4, the D.C. circuit’s ruling would stand. But sources cautioned this was less likely.

“The earliest the Supreme Court could possibly hear it for oral argument would likely be next February or March, and it could possibly not be until the following October depending on how long the [D.C. circuit] decision takes,” said Lazarus. He added that if there is still no ninth justice at that time, the Court might opt to delay certain arguments and rulings until there is a full bench.

There’s one more wrinkle to all this, Gerrard added. “Several states that litigated against the Clean Power Plan are now considering whether to undertake planning under the plan despite the stay, and it will be interesting to see whether this development influences the thinking of some of these states,” he said. If it does, that means many of the rule’s effects could enter force as prudent local utilities engage in cost-benefit analysis, even if the rule itself does not.

Ultimately, the opening of a new slot on the Supreme Court makes the Clean Power Plan’s survival much likelier—if a Democrat wins the White House in November. The Plan might also enter force if a Court with a vacant seat hears its case. But then the country will have other problems.