While Washington was glued to the New Hampshire primary results, the Supreme Court dropped a bombshell, placing a hold on the core of President Obama’s global warming policy, the Clean Power Plan. This will inevitably prompt speculation that the five conservative justices meant to tie up the program in litigation until Obama is out of office; but there are more charitable interpretations. What would not be so understandable is if the court ultimately ripped the plan apart.

Technically, the law’s challengers needed to show “a likelihood of success on the merits” to warrant a stay. They did not convince a federal appeals court that they deserved one. But in a 5-to-4 decision, the Supreme Court took the extraordinary step of overruling that call. It is hard to divine the justices’ thinking, but there are several reasons, beyond pure partisanship, that could have motivated them. Half the states are challenging the Clean Power Plan; the justices may have felt that this wide body of states deserved some respect and acknowledgment. Or they may still be smarting from a decision they made last term, in which they struck down an Environmental Protection Agency rule only to hear boasting from environmentalists that companies had largely complied with the voided rule before the decision came down. This may be the justices’ way of making clear that the EPA should not expect that to happen again.

All that said, the Clean Power Plan’s challengers do not have as strong a case as the court’s remarkable action would seem to suggest. They rely heavily on the notion that the Obama administration should be barred from using a powerful Clean Air Act tool to set emissions standards on power plants, though there is no more fitting tool to the task in the act. They also condemn how the EPA would use that standard-setting power, insisting that the agency look at individual facilities rather than state power systems as a whole, which would make the rule much more expensive or much less powerful. Should the challengers prevail on the grounds they propose, the Supreme Court may rule that the EPA has the power to regulate the greenhouse gases — but not effectively.

As it is, the stay will have policy effects. The EPA will not be able to do anything but cooperate with states that voluntarily seek to cut greenhouse gases to prepare for the eventuality that the Clean Power Plan is implemented. The compliance time frame is years long, but states and utilities should be working now, because electrical utility investment and planning takes time.

The stay should also wake up Congress. The Clean Power Plan’s legal issues arise from the fact that the Clean Air Act is a decades-old law that was not written to deal with the unique challenge that greenhouse-gas emissions pose. There is still a good case for applying the act to the task, given that it was built to be a powerful check on a range of threatening emissions. But lawmakers could write a simultaneously more effective and less expensive climate strategy. It is called a carbon tax, and, if well-designed, it could make all of this legal wrangling moot.