When President Barack Obama was pledging to lower US greenhouse gas emissions in Paris last week, Republicans in Congress were passing measures to ease controls on carbon pollution from power plants.

These moves in Washington won’t actually hamper the president’s goals that much though, says Robert Stavins at Harvard’s Kennedy School of Government. The president will veto the measures and Stavins says the US will be able to reduce its emissions through a combination of ways.

“There’s going to be reliance on state-level actions, importantly California, as well as in the northeast states (through) the Regional Greenhouse Gas Initiative.”

Then there are the fuel economy standards enacted by President George W. Bush with bipartisan support in Congress, then made tougher under President Obama. Those rules have been in place for several years now and are unlikely to be undone.

Follow all of our coverage of the Paris talks and the global climate crisis

A major goal in Paris is to devise a path to keep global temperatures from rising more than 2 degrees Celsius (3.6 Fahrenheit) over pre-industrial levels. In the past few days, there’s been a growing chorus of voices from the world's most vulnerable counties, and some less vulenrable ones, calling for a more aggressive target limiting any temperature rise to 1.5 degrees Celsius. That will be a challenge, considering that greenhouse gases continue to rise quickly, and global temperatures have already risen 1 degree.

The US signed and ratified the treaty that underlies this whole process in 1992: the United Nations Framework Convention on Climate Change drafted in Rio de Janeiro. So, any agreements reached in Paris this week would fall under existing international law and would not have to be ratified by Congress. The 1992 agreement didn’t set mandatory limits on greenhouse gas emissions, however; it set voluntary non-binding aims that the world’s leaders are hoping to advance in Paris. President Obama has pledged to lower US greenhouse gas emissions by 26 to 28 percent from 2005 levels within 10 years.

If you listen to many of the Republican presidential candidates, though, they are committed to stopping agreements made this week. Carly Fiorina called Obama “delusional” on the matter. Mike Huckabee labelled the president as “clueless.” Donald Trump said China is “laughing at us.”

If one of these candidates took over the White House, Stavins says he or she could undo mechanisms to lower greenhouse gases, in theory. But Stavins doesn’t think that’s likely for economic reasons. For example, the Environmental Protection Agency has already introduced new mandates to curb greenhouse gases — public utilities and electricity generators are busy forming plans to comply.

“If the government then comes in two, three, four years from now and says, ‘Sorry, we’ve changed our mind, you’re no longer going to be rewarded for low-carbon energy investments,’ the government would be creating stranded assets for those companies,” says Stavins. “So I think that the companies are actually going to be on board and will be quite resistant to it being rolled back years from now.”

Oren Cass with the conservative, or free market, think-tank the Manhattan Institute disagrees. He thinks President Obama’s Clean Power Plan — curbing carbon from power plants — would be doomed with a Republican in the White House. President Obama only announced the details of the plan in August.

“That is the centerpiece of his agenda and will not survive a Republican administration. And that could be reversed before the market and power companies have taken significant action in pursuit of it,” says Cass.

At least 24 lawsuits nationwide have also been filed to derail, or at least slow down the Clean Power Plan after the plan was published in the federal registry in October.

Conservatives have other ways to try and thwart what the Obama Administration agrees to this week. One of the things delegates are discussing in Paris is transferring money — hundreds of billions of dollars — from wealthy nations to poorer ones to help them adapt to a low-carbon future. Cass calls this a “ransom,” one that’s dead on arrival in the Republican-controlled Congress.

“There are all sorts of disputes about what a president can and cannot do by himself, but everybody agrees that the president can’t appropriate the money,” says Cass. “I think Paris is a big waste of time. I think it’s worse than a big waste of time.”

Bottom-line: Cass, and many conservatives say the Obama Administration is committing to too much this week in Paris.

I asked Kelly Sims Gallagher, director of the Center for International Environment & Resource Policy at Tuft University’s Fletcher School of Law and Diplomacy, what a Republican president — one who opposes action on climate change — could mean for any progress reached in Paris this week.

“It does jeopardize the international momentum that we have. If the United States fails to meet its targets, it will lose the moral authority to encourage and cajole other countries to honor their commitments as well,” says Gallagher, who also served in the Obama Administration as a senior policy advisor in the White House Office of Science and Technology Policy.

Gallagher says international law is soft and it's difficult to enforce commitments — the best path forward is to lead is by example. She adds that if the Republicans don’t like the president’s approach to curbing greenhouse gases, it would be helpful for them to devise some of their own.