A federal appeals court panel is hearing a challenge to Obama's rule by industry groups and a number of states, and that ruling will go a long way toward shaping the regulation's fate.
If the U.S. Court of Appeals for the District of Columbia Circuit decides to leave the rule intact, environmentalists could argue there is no need to rewrite the plan. If the court finds fault with large parts or all of the plan, Trump could cite the decision to claim the regulation was fundamentally flawed.
The Supreme Court stayed implementation of the rule in February 2016 while the lower court considers arguments.
Once the EPA begins the rule-making process, it can petition the court to pause proceedings, since the Clean Power Plan will be overhauled. Alternately, the agency could argue that the court should drop the case outright.
Bruce Huber, associate professor of law at Notre Dame, said the latter is unlikely because the courts typically do not end deliberation until a new rule is close to being finalized, and the EPA has not even started that process.
"This was such a high profile case that I don't think they would," he said.
But Brookings Institution senior fellow Philip Wallach believes the DC Circuit Court will back down for exactly that reason.
The DC Circuit is seen as a stepping stone to the Supreme Court, and judges anticipating future confirmation hearings are generally amenable to handing off tough decisions on hotly disputed topics, according to Wallach. Trump's move to rewrite the plan presents just the sort of political solution that gives panelists an out, he said.
"It looks pretty convenient to the DC Circuit to let things proceed without having to render an opinion," he said.
One thing the experts agree on: The EPA's rule is sure to face litigation.
"So much of the environmental advocacy community is really deeply devoted to defending the Clean Power Plan, even if they don't have that many prospects for winning over this administration, getting something to go into effect seems to be a hill they're willing to die on," Wallach said.