Even if this spring’s roller-coaster weather doesn’t put global warming on the national agenda for most Americans, the Supreme Court has now made sure the issue will be front and center in the presidential campaign.

Last week, in a big blow to George W. Bush’s firm stand against economic regulation, the court told the EPA to reconsider its longstanding decision against regulating carbon dioxide or other pollutants contributing to climate change. Essentially, the court told the administration it does in fact have powers it says it doesn’t have. That has been a comfortable political position for Bush and many Republicans, who have long argued that it would harm the economy to impose mandatory controls on greenhouse gases — the emissions from cars, trucks and factories that trap heat close to Earth’s surface.

The decision, in one of the most important environmental cases ever to reach the Supreme Court, puts enormous pressure on politicians in both parties — and especially on the presidential aspirants — to take global warming seriously. And with foot-dragging for its remaining 20 months the administration’s likely response to the ruling, it will be up to the next president to either heed the justices’ call to action or continue to do little and risk further court involvement. Also, the 5-4 vote in the case shows how the next president’s judicial nominees could potentially shift the court’s view to either a stronger majority or a reversal.

The issue sets up a classic debate between the parties over the role of government in the private sector. Democrats, pressed most prominently by their 2000 nominee, Al Gore, are overwhelmingly behind more regulation, although they’re arguing over his endorsement of higher taxes to prod industry. Most Republicans, like the president, have dropped their skepticism about the nature of the problem but join Bush’s opposition to regulation.

So far, presidential contenders in both parties have mostly stuck to platitudes when addressing the issue, although Republican John McCain is on record in the Senate for mandatory caps on greenhouse gas emissions, and Democrat John Edwards has proposed requiring new coal-fired power plants to apply technology that contains carbon dioxide emissions. Republican Rudolph Giuliani exemplifies the vagueness of so many candidates on the subject — the former New York mayor’s most specific statement so far has been to acknowledge, “I do believe there’s global warming.”

Gore’s name didn’t come up in the Supreme Court opinions, but you have to wonder whether the justices would have come down so hard on Bush’s EPA had the former vice president not made the issue so high-profile. His Oscar-winning documentary predicting the grim effects of global warming, “An Inconvenient Truth,” has kept thoughts of another Gore presidential bid alive in the hearts of many voters. He was greeted as a champion on Capitol Hill when he testified about global warming.

Democrats running for president are moving quickly to take up Gore’s cause and reap the benefits before he has a chance to ride the issue into the race. The Gore factor has positioned Democrats to be seen as more likely than Republicans to please those voters who want something done.

The political effect of the Supreme Court decision on the GOP is profound. The party no longer has the option of avoiding regulation on the theory, advanced by the administration but rejected by the justices, that the federal government has no power to impose mandatory controls. And, far from going away, the issue is likely to come back to the high court before Election Day 2008. The very case on which the justices ruled last week is likely to come before them again because the EPA essentially was ordered to reconsider its stand and get back to the justices.

With a majority squarely on the side of pushing the federal government to take action, elected officials must do something or, as the court noted in its ruling, make a convincing case for why nothing should be done. And the justices signaled that they would accept inaction only if the EPA were to adopt and convincingly defend the position that global warming is not for real. The agency can’t avoid its “legal obligation,” John Paul Stevens wrote for the majority, by noting the scientific uncertainty surrounding some features of climate change and concluding that it would be better not to regulate at this time. But the White House seemed unmoved, at least in its initial reaction to the ruling. “We’re going to have to take a look and analyze it and see where we go from there,” spokeswoman Dana Perino said.

While this administration commits only “to take a look,” the Republicans and Democrats who want to run the next administration will be pressed to grapple with the tough measures that might please many voters — but irritate the powerful corporate interests who are still going to finance most of the coming campaign.

Contributing Editor Craig Crawford is a news analyst for NBC, MSNBC and CNBC. He can be reached at ccrawford@cq.com.