Opinion writer

At a press conference in Paris today, President Obama was asked a good question: Even if we do achieve a global climate deal, what are the odds that the United States will keep its commitments to it, given that a Republican president may succeed you?

Since the GOP candidates have condemned Obama’s overall climate agenda — and since they regard it as self-evident that relying on countries like China to limit their own carbon emissions is nothing more than a thigh-slappingly hilarious delusion — surely a GOP president would simply scuttle our participation in such an agreement. Right?

Yes, a Republican president could pull us out of any such agreement, lawyers tell me. But in reality, it might be more forbidding than it looks.

There are two ways the next GOP president could scuttle our participation in such an international agreement, in which participating countries would all pledge to reduce their carbon dioxide emissions. The first, most direct way is by pulling the United States out of it. The second, less direct way would be to roll back Obama’s Clean Power Plan, which seeks to reduce carbon emissions from power plants and thus may be pivotal to whether we can meet our end of the bargain.

The eventual GOP nominee will very likely be on record pledging to do both of these. Whether he actually would do so as president is another matter entirely.

The GOP president could pull us out of the agreement. Any eventual deal in Paris will not be a treaty for purposes of U.S. law. since there is no chance the GOP-controlled Senate would ever ratify it. Instead, it would be a blend of an “executive agreement,” the name given to international agreements that do not need Senate approval, and an agreement to update the 1992 United Nations Framework Convention on Climate Change treaty, which would not require Senate approval, since it was already approved.

Today Obama said that he hopes the final Paris accord has “legally binding” elements.  But there’s some confusion around what this means.

According to Nigel Purvis, a D.C.-based climate consultant and former treaty lawyer, Obama is not saying he would seek any changes in U.S. law. Rather, he’s simply saying he wants elements of the agreement to be binding under international law. The participants would pledge to hit certain carbon-reduction targets (which would not be obligated under international law), but they would also pledge to verify the implementation of a plan to accomplish that, and to return periodically to renegotiate ever stricter targets (both those steps would be binding through updating the aforementioned UN framework, even if the targets themselves aren’t). The ever stricter targets are necessary because the front-end commitments that are expected won’t be nearly enough to achieve the scientific goal of limiting warming to two degrees Celsius, so more big steps will be necessary in out years.

A Republican president could theoretically pull us out of this agreement, and Purvis tells me he expects that it will have a built-in process for this. “Most international agreements contain provisions for a party to withdraw, and this agreement is likely to do that as well,” Purvis says. “Usually what is required is notice. This would allow any U.S. president to withdraw within roughly a year or so after giving notice to the international community.”

But Purvis predicts that this could look a whole lot more difficult from the Oval Office than it currently does from the campaign trail — because withdrawing would alienate allies. In this sense, this could be similar to the pledge by GOP candidates to tear up the nuclear deal with Iran on Day One: it’s a GOP-base-pleaser, but it would have all sorts of unintended international consequences a GOP president might not want to risk. “An agreement will generate very strong expectations from our allies,” Purvis says. “We need Europe on ISIS. They need us on climate. There’s a web of dependence.”

Still, a Republican president could serve notice to the international community that we’re pulling out of any such deal.

A GOP president could roll back the Clean Power Plan. States and power companies are already suing to block the CPP — which aims to reduce carbon dioxide emissions from U.S. power plants by 32 percent by the year 2030, relative to 2005 levels, by setting targets for states to meet. The legal dispute may not be resolved until 2017 and may fail.

But a GOP president taking over in 2017 could still undo it in several ways. One would be to roll back the CPP through a rules change, since the CPP itself is an Environmental Protection Agency rule premised on the authority it is granted under the 1970 Clean Air Act. But according to New York University law professor Richard Revesz, that process might take years and could itself be subject to a court challenge. A GOP president and a GOP Congress could pass legislation rolling it back, but a change to Senate rules might be required to get that past a Dem filibuster. “There are some things a Republican president might to do try to undermine the CPP, but his discretion might be limited in significant ways,” Revesz tells me.

But Jonathan Adler, a law professor at Case Western Reserve University, points out that a GOP administration’s EPA would not be obliged to implement the CPP while those processes played out, undermining our participation in a global deal. “Legally a Republican president would be able to walk away from anything the U.S. agrees to in Paris, and would likely be able to unravel the Clean Power Plan,” Adler says. All this seems possible, but it remains to be seen how easy it would be.

But would a GOP president go through with it? Today, Obama suggested he wouldn’t, noting that such dilemmas look very different from the vantage point of the Oval Office than from that of the campaign trail.

“Your credibility and America’s ability to influence events depends on taking seriously what other countries care about,” he told reporters. “Everybody else is taking climate change really seriously. They think it’s a really big problem.” Obama added that the next president will come face to face with a global consensus behind action, and as a result, he or she “is going to need to think this is really important.”

And so, the eventual GOP nominee will be on record pledging to yank the U.S. out of a global climate deal, which he could do. But if a deal is reached, and it is being implemented, it’s not clear that vowing to roll back that progress will play all that well to a general election audience. One in office, pulling out of the agreement might not appear all that desirable, given the untold consequences it could unleash. And while rolling back the Clean Power Plan would definitely complicate our participation in any agreement, that’s hardly an easy slam dunk, either.