Now, Republican critics are threatening to withhold funding that the president promised to set aside to help developing nations curb emissions and brace for the impact of global warming. The administration insists it will find a way to secure the funds, but as with many of the president’s climate commitments, it’s unclear if the White House can deliver on that promise.

There are indications that the rest of the world isn’t overly concerned by opposition in Congress. “Yeah, fine,” United Nations climate official Christiana Figueres reportedly said at a press conference when asked to comment on Republican attempts to undermine the president’s global-warming effort.

Still, the president’s climate agenda is unquestionably under threat. Lawsuits have taken aim at many of the environmental regulations issued by the administration. Future presidents could undermine or attempt to reverse the agenda. Congress will also continue to look for ways to thwart the president’s environmental regulations.

“We want to the world to know that there are differences of opinion between the Congress and the president on this issue and on his clean energy plan,” Republican Representative Ed Whitfield of Kentucky said on the House floor on Tuesday.

The president has waved away the idea that Republicans on Capitol Hill can derail the Paris talks. “It may be hard for Republicans to support something that I’m doing, but that’s more a matter of the games Washington plays,” he told reporters on Tuesday. “That’s why I think people should be confident that we’ll meet our commitments.”

But Obama is acutely aware of the challenge posed by global warming. The Paris talks are only a first step. Ultimately, developed nations like the United States must transition away from fossil fuels if they wish to substantially curb greenhouse gas emissions. That challenge extends long beyond the time Obama will occupy the Oval Office.

The president has dismissed the idea that America will elect a Republican president intent on tearing down his legacy. (“I’m anticipating a Democrat succeeding me,” he said Tuesday.) And Obama insists that whatever the outcome of the election, future administrations will be compelled to confront global warming, not least by the weight of international pressure.

“There’s a reason why you have the largest gathering of world leaders probably in human history here in Paris,” he said. “Everybody else is taking climate change really seriously.”

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