Former Secretary of State John Kerry doesn't trust President Trump to negotiate a better deal than the Paris Agreement when it comes to fighting climate change, comparing it to O.J. Simpson's pledge to find "the real killer" of his ex-wife and her boyfriend.

"When Donald Trump says to the world ‘well we are gonna negotiate a better deal' … that is like O.J. Simpson saying he is going to go out and find the real killer," Kerry said. "Everybody knows he isn't going to do that because he doesn't believe in it. If he did believe in it then he wouldn't pull out of Paris. America has unilaterally ceded global leadership on this issue."

Kerry said he doesn't have any regrets that the Obama administration didn't try to get the Paris Agreement ratified in the Senate to make it harder for President Trump to exit the agreement.

"It wouldn't have happened," Kerry told NBC's Chuck Todd on "Meet the Press" Sunday, referring to whether the Senate would ratify the Paris agreement. "The president made an executive agreement because that was the best that we could do."

Because Paris was not ratified like a normal treaty when it was finished in 2015, Trump had executive fiat to exit the worldwide climate agreement. He chose to exit it this past week, arguing the agreement would hurt the U.S. economy.

Todd referenced a quote from Kerry a few years ago in which the former secretary doubted that a Republican would win the White House and reverse the accords.

Kerry told Todd that he didn't think the U.S. would pull out of the agreement. He conceded that supporters of the Paris deal lost a messaging battle on the economy after admitting that President Trump's base cheered the decision to exit.

"We presumed that common sense and basic economics and science would prevail," he said. "I didn't think we would see how the Republican Party has traveled lock, stock and barrel into the hands of the Koch brothers and special interests."