President Donald Trump ridiculed former Secretary of State John Kerry on Monday for refusing to rule out a 2020 presidential run.

“I see that John Kerry, the father of the now terminated Iran deal, is thinking of running for President,” Trump wrote. “I should only be so lucky – although the field that is currently assembling looks really good.”

Margaret Brennan, host of Face the Nation, asked Kerry on Sunday about a 2020 run.

“I’m really not thinking about it. Talking about 2020 right now is a total distraction and waste of time,” Kerry replied, urging more attention on the 2018 midterm elections.

Kerry said he would continue to be an “activist” and promised to keep fighting for the leftist agenda, signaling disappointment that Trump withdrew the United States from the Iran deal that he helped negotiate.

Despite his frustration with Trump’s decision, he said he would not respond to the president’s insults on Twitter.

“I think America and our democracy are more thoughtful than dishonest tweets,” Kerry told the CBS host.

Kerry famously lost to George W. Bush in 2004, running as the Democrat nominee with Sen. John Edwards as his running mate. Edward was later caught in a sex scandal with a campaign staffer.

Kerry said he regretted choosing Edwards as his running mate.

“If you measure the qualities that you are looking for when you choose a vice president,” he said, “it didn’t measure up. It wasn’t what we had hoped for”: