John Kerry served as the Secretary of State under Barack Obama for four years and was the 2004 Democratic presidential nominee, losing to George. W. Bush. According to Kerry, if he were to have a meeting with incumbent President Donald Trump, he would tell him to resign.

Attending a World Economic Forum panel in Davos, Switzerland, Kerry spoke with CNBC’s Tania Bryer. She inquired about how a meeting between the two prolific politicians would go. “I can’t play that because he doesn’t take any of this seriously. He doesn’t have an ability to have that kind of conversation,” Kerry responded. When asked what his message to Trump would entail, Kerry answered back with only one word: “Resign.”

The former Senator was also critical of Trump for pulling out of the Paris accord in 2017. “I wish there was a lawsuit capacity that could hold people liable for such an insane decision as he has made, which is going to cost lives,” Kerry continued. “People will die because of the President’s decision, and billions of dollars of damage will be done to property.”

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Kerry added how he was disappointed in Trump for being dishonest in his reasoning for leaving the accord. As he withdrew from it, Trump claimed he was doing so in order to receive “fair treatment,” claiming his international counterparts across the global stage were laughing at the United States. “I’m disappointed when a president of the United States lies, and that was a lie – there’s no burden,” Kerry sighed. “Paris did not place outside burdens levied by any other country on any other country.”

Speaking last November, Kerry admitted that he open to pursuing another presidential run in 2020, saying he isn’t “taking anything off the table.”