Former senator and Secretary of State John Kerry said Wednesday he has no plans to run for president in 2020, but didn't rule out the idea.

"I don't have any plans right now, honestly," Kerry said on MSNBC when asked if he might make another run.

Host Joe Scarborough and others noted that wasn't a firm denial, and pressed Kerry to talk more about whether he would entertain a run.

"You're a troublemaker," Kerry replied.

Scarborough noted that Kerry is younger than some of the Democrats who might run against President Trump in 2020, such as Sen. Bernie Sanders.

Kerry was the Democratic presidential nominee in 2004, when he lost to President George W. Bush.

Kerry criticized Trump for delivering a speech to the United Nations that he said focused too much on "America first."

"The president gave a speech about America first, which winds up in effect, I think, making America last and diplomacy last, or making America alone," Kerry said. "It pushes people away."

Kerry, like his predecessor Madeleine Albright, also criticized Trump for calling North Korean leader Kim Jong Un "Rocket Man."

"If name calling was going to solve this problem, Donald Trump would have already solved the problem," he said.