Perhaps the unluckiest people in American politics are those battling climate change. On Monday, they will join allies at the Supreme Court to fight for an aspect of the EPA's ability to regulate greenhouse gas emissions precisely at the moment that the national political debate has become focused on President Obama's use of his executive authority — like EPA regulations. For many reasons, the timing couldn't be worse.

The case at hand, Utility Air Regulatory Group v. EPA, is complicated, so a quick primer is in order. The question at stake is whether the EPA has the right to consider greenhouse gas emissions in industrial permits, and if it has the right to change the levels of pollution that it would allow.

In Massachusetts v. the United States in 2007, the Supreme Court determined that greenhouse gasses, like carbon dioxide, are pollutants, which, under the Clean Air Act, the EPA has the authority to regulate. But the agency has dragged its feet on regulating carbon emissions, in part because such regulations are tricky to develop and in part because there hasn't been much political will to do so. One aspect of that regulation involves taking greenhouse gas pollution into consideration when the EPA grants upgrade permits. Want to build out your power plant? Under the authority of that 2007 decision, the EPA can also require you to reduce your carbon emissions.

At least, as the EPA understands that decision. The 2007 decision dealt with pollution from cars, which the EPA took as implying broader authority. The other question is that the EPA's baseline standard for what constitutes too much pollution from a source is low. After all, the Clean Air Act preceded popular understanding of climate change, and was at the time focused more immediately harmful pollutants like mercury. Instead of considering 100 or 250 tons of carbon dioxide an amount of pollution that would trigger questions for permitting, the EPA raised the level of allowable CO2 to an amount that would only capture the biggest emitters.

That, in the view of people who oppose the EPA, is an exercise of executive authority outside the bounds of the EPA's mandate. If the Clean Air Act, passed by Congress, says you that the limit is 250 tons, then the limit is 250 tons. And if the EPA can unilaterally regulate carbon emissions of anything, eventually everyone emitting at those lower levels — basically any commercial entity — would be subject to expensive upgrades.

Obama's opponents have seized upon the argument that he's pushing the boundaries of his authority, both because he has — as with his past recess appointments — and because he has promised to act where Congress refuses to, as he did in his State of the Union address. In fact, the EPA's ongoing development of rules setting standards for carbon dioxide pollution only really got underway after Obama asked Congress to act on climate change during his 2013 State of the Union address and it failed to do so. (Those rules, will which eventually set caps on emissions outside the permitting process, aren't affected by the Court's consideration on this issue.)

In an editorial supporting the EPA' authority, The New York Times outlined the two sides neatly. "As with most battles over environmental regulation," it wrote, "the struggle is between the bottom-line economic concerns of business and the government’s reasonable efforts to protect human health and the environment." The people suing the EPA aren't worried about developing the best solution to climate change; they're worried about the economic effects of that regulation and about a government agency that's empowered to impose those economic effects.

That's the bigger problem at stake for the EPA. While the Supreme Court has repeatedly upheld that the agency can regulate carbon dioxide emissions, its ability to do so is dependent on the will of the president — as we've seen in the general inaction from George W. Bush and Obama's decision to wait until after his reelection to give the EPA free rein on developing standards. The Washington Post quotes Harvard's Richard Lazarus saying, "If the EPA loses, 'you can be sure the court's decision will be read as a repudiation of what Obama’s doing.'"

"The question is who gets to decide the best way to go about reducing harmful emissions," the Times editorial board writes, though that's only partly true. The question is apparently whether or not anything is done at all. If the Supreme Court tells the EPA that its attempts to apply its authority have been excessive, it could make the Obama administration (and future administrations) wary of acting at all.

Update, 5:00 p.m.: Justice Anthony Kennedy, often the swing justice on ideological battles, seemed to express skepticism about the EPA's use of its power in oral arguments, according to The Hill.

“I couldn't find a single precedent that supports [EPA's] position,” Kennedy told Solicitor General Donald Verrilli during oral arguments on the case Monday. 

Kennedy was joined in his skepticism by the court’s four conservative justices, while liberals on the court generally backed the EPA’s interpretation of its powers under the Clean Air Act.