“Late Show” host Stephen Colbert compared President Trump on Tuesday to a “reminiscing” grandfather after Trump called the Justice Department part of the “deep state,” a reference to a conspiracy theory about a behind-the-scenes bureaucracy controlling the government.

“Crooked Hillary Clinton’s top aid, Huma Abedin, has been accused of disregarding basic security protocols. She put Classified Passwords into the hands of foreign agents,” Trump tweeted earlier Tuesday. “Remember sailors pictures on submarine? Jail! Deep State Justice Dept must finally act? Also on Comey & others.”

“‘Remember sailors’ pictures on submarine?’” Colbert asked in reference to the tweet. “I think grandpa’s reminiscing again.”

Colbert, returning back to television after a winter holiday break, noted that Trump “described the Justice Department as a deep-state entity because it is so corrupt it is unwilling to throw his political opponents in jail.”

“That is a serious charge, and the kind of thing you could never, ever make lightly, and of course you could never take back,” Colbert added. After a brief pause, he said, “I’m kidding.”

Colbert said he was kidding because White House press secretary Sarah Sanders defended Trump’s comments during the White House press briefing on Tuesday.

“Obviously he doesn’t believe the entire Justice Department is part of that," Sanders said. "You know, one of the things the president has done is appoint Christopher Wray at the FBI because he wants to change the culture of that agency.”

Colbert also took a jab at Trump for touting that there were no deaths in commercial aviation in 2017, something Trump “had absolutely nothing to do with.”

“Since taking office I have been very strict on Commercial Aviation,” Trump said in his Tuesday tweet. “Good news - it was just reported that there were Zero deaths in 2017, the best and safest year on record!”

“Trump took credit for no one dying in a plane crash this year,” Colbert said. “That explains his new campaign slogan: ‘Trump 2020: You got to Tulsa, didn’t ya?’”