You know the situation is bad when Rex Tillerson, the longtime fossil fuel baron and former CEO of ExxonMobil, is among the most reasonable voices in the room. 

The Trump administration’s promised assault on President Obama’s climate action legacy is well underway. This week, President Trump is expected to sign an executive order directing the Environmental Protection Agency to start unraveling the Clean Power Plan, Obama’s effort to reduce carbon pollution from power plants. The White House is scheming with Big Auto to roll back Obama-era increases in vehicle fuel efficiency as it conspires with Congressional Republicans to undo rules that address oil and gas wells’ leakage of methane, a heat-trapping gas that is about 80 times more powerful than carbon dioxide. Trump’s forthcoming budget even threatens to dismantle the EPA’s Energy Star program, a 20-year-old initiative that encourages the adoption of energy-efficient appliances and home heating and cooling—a program that, historically, has enjoyed bipartisan support since it saves Americans money. 

All of this has environmentalists wondering when the other shoe will drop: Are these moves just the first steps toward a feared U.S. retreat from the Paris Climate Agreement? 

During last year’s presidential campaign, Trump promised that, if elected, he would “cancel” the Paris Agreement. But during his Senate confirmation hearings, Secretary of State Tillerson argued that the United States should keep “a seat at the table.” According to various reports (see here and here) White House advisors are split on the issue. While svengali Stephen Bannon is said to be arguing for a Paris pullout—a position in-line with his hardline nationalist vision—Tillerson and Ivanka Trump and consigliere/son-in-law Jared Kushner are making the case that the United States should remain a party to the international agreement. 

Environmentalists, meanwhile, are feeling a bit left in the dark. “I think my crystal ball broke months ago,” Vicki Arroyo, director of the Georgetown Climate Center, says wryly. “I wouldn’t want to make a prediction.” Jennifer Morgan, the executive director of Greenpeace International and a longtime fixture at international climate talks, told me much the same thing: “You know, with this administration, it’s impossible to know anything.” 

Still, longtime climate action advocates are trying to remain guardedly optimistic, hopeful that, in the end, reason will prevail and that career diplomats at the State Department will successfully convince the White House to keep the United States within the Paris Agreement. A U.S. withdrawal would be nothing short of a “nuclear option,” in Arroyo’s words, that would erode American credibility and set back U.S. interests on other issues requiring global cooperation. “Aggravating our allies and walking away from an agreement that we helped craft is not a great practice,” Arroyo says. “It would undermine us on other issues that we care about.” 

What would it look like if the United States were to remain a party to the climate accord, even as it retreated from its pledges to reduce its domestic greenhouse gas emissions? 

In one scenario—the most optimistic—the U.S. would simply step aside and be an observer of sorts as other nations continue on the path toward ratcheting down emissions (the commitments established under the Paris Agreement don’t begin until 2020). More worrisome is the prospect that the U.S. would become an obstructionist presence within the U.N.-sponsored talks. “If the U.S. keeps a seat at Paris but starts taking ideological positions to push for a watered down structure of the agreement … that would be harmful,” says Andrew Light, a senior fellow at the World Resources Institute and a former State Department climate envoy. 

But, Light says, the Trump administration’s ability to wreak havoc would be limited. The U.N. Framework on Climate Change operates on a consensus basis, and while that can be a weakness—as it allows oil producers like Saudi Arabia to lobby for unambitious goals —it can also be a strength as it limits the ability of bad actors to skew the process. “You can slow things down, but you can’t throw in a bombshell,” Light says. 

Also, any attempts by the United States to toss sand in the gears of the U.N. process would face a powerful backlash from other nations. That’s exactly what happened in 2007 during the climate talks in Bali, Indonesia, when smaller countries demanding climate justice shamed the Bush administration. At that meeting, a negotiator from Papua New Guinea demanded that the U.S. “get out of the way” if it wasn’t willing to be a constructive player—forcing a retreat. “The U.S. negotiators got booed, and it sort of changed their position,” Arroyo remembers. 

Even as environmentalists hope for the best, they are also preparing for the worst: a U.S. withdrawal from the Paris Agreement (which actually would take four years) or, even more frightening, a pullout from the entire U.N. framework. 

What would be the consequences of such moves? Climate action advocates worry that it could spur other nations to also exit—unlikely, but still a risk. Although that would not nullify the agreement (the agreement would still cover well more than 55 percent of global emissions, as required by the deal, which you can see from this WRI-sponsored tracker), it would be a geopolitical setback. At the very least, a U.S. withdrawal might lead to foot-dragging by other countries. 

Though a U.S. exit would be a blow, environmentalists say that global action to reduce greenhouse gas emission will nevertheless continue. The world’s largest emitter, China, remains committed to ambitious climate action; its greenhouse gas emissions have stayed stable or in decline for four years in a row. The European Union member nations and the many countries—think, Bangladesh, Pacific Island nations, poorer countries in Latin America and Africa—that are already experiencing stresses due to climate change also remain committed to fulfilling their Paris pledges. “There is an unprecedented show of unity from nations around the world,” Arroyo says. “Countries are standing together and they are sticking with it [the Paris Agreement]. In a surprising turnaround since [the 2009 climate talks in] Copenhagen, China is taking a lead. It can show international leadership with the vacuum of U.S. leadership.” 

With or without the United States, much of the rest of the world is committed to addressing the climate crisis. That is, of course, good news for the planet’s ecosystems and for human civilization. But it’s also a depressing commentary on the global reputation of the United States in the Trump era. A vacuum of U.S. leadership, Arroyo said. For those of us Americans who believe in the ideals of international cooperation, the Trump administration’s myopic view of U.S. interests is heartbreaking. 

Trump likes to say that he’s going to “Make America Great Again,” and put “America First.” A withdrawal from global climate agreements would do neither. It would, instead, be a retreat from the U.S.’s moral responsibility to address the climate crisis. It would put the U.S. last, a country playing catch-up to other countries heading toward the clean energy future.