"Every four years, candidates descend on the Iowa State Fair to narrow the field by clogging their arteries," Stephen Colbert said on Monday's Late Show, documenting some of the fried and breaded things the 2020 Democrats ate. "Some Democratic candidates are trying to differentiate themselves from the pack by releasing plans," he added. "My favorite so far is this one: Bernie Sanders says that if he's elected, he'll reveal whether aliens are real."

But "one candidate had a particularly bad weekend in Iowa," Colbert said: Joe Biden. It started when he "said a whoopsie" at a town hall in Des Moines, suggesting "white kids" are the opposite of "poor kids." Still, when President Trump tried to mock Biden as mentally unfit for saying Democrats believe "truth over facts," Trump "got being wrong wrong," he added. "Also, I believe this is a case of the pot calling the kettle mentally unfit."

Trump mocked "Biden on Twitter, saying 'Does anybody really believe he's mentally fit to be president?'" Seth Meyers said at Late Night. "That would be a great question — if anybody else was asking it. But this is like having the crazy guy in the subway walk up to you and say 'Can you believe this other guy?'"

"Joe Biden made not one but two dopey comments at the Iowa State Fair," Jimmy Kimmel said on Kimmel Live, showing them. "At least he's saying this stuff by accident. But Biden isn't backing down, he's not making excuses. This is a man who speaks his mind, whether it makes a bit of sense or not." He illustrated his point with a fake Biden campaign ad.