John Podesta, former chairman of Hillary Clinton’s 2016 presidential campaign, wrote in an op-ed that “I had nothing to do with the Democratic National Committee. . . . So there was no DNC server for me to refuse to give.” (Kristoffer Tripplaar/For The Washington Post)

On a full day of meetings Friday at the Group of 20 summit in Hamburg, President Trump fired off one of his more curious tweets of late: a claim that “everyone” there was talking about the role of John Podesta, Hillary Clinton’s former campaign chairman, in last year’s Russian email hacking scandal.

“Everyone here is talking about why John Podesta refused to give the DNC server to the FBI and the CIA. Disgraceful!” Trump wrote, apparently referring erroneously to a Democratic National Committee server that contained emails that were hacked and made public.

Podesta, who was taking a cross-country car trip with his wife Friday, said he discovered during a pit stop in West Virginia that the president was tweeting about him. He fired back in kind on Twitter, calling Trump “our whack job POTUS” and telling him to “get a grip man.”

Trump’s tweet followed several others Friday in which he recounted meetings with world leaders at the G-20 summit, and it came just hours before he was scheduled to sit down with Russian President Vladimir Putin, who U.S. intelligence officials have said directed his country’s meddling in last year’s election between Trump and Clinton.

President Trump meets with Russian President Vladimir Putin at the Group of 20 summit Friday in Hamburg. (Evan Vucci/AP)

Trump’s tweet conflated two parts of the email scandal. Email hacked from the DNC server surfaced last July, while hacked email from Podesta’s personal…