The pointed criticism from the older statesman to the younger bore a distant echo to the 1988 vice presidential debate when Texas Democratic Sen. Lloyd Bentsen tore into Indiana GOP Sen. Dan Quayle, telling him “Senator, you’re no Jack Kennedy.”

Unlike Quayle, who compared himself to Kennedy, Buttigieg has not explicitly said he’s like Obama, although his supporters have said he reminds them of the former president and staffers have drawn oblique parallels.

Biden’s remarks came hours after his campaign released a web ad that mockingly compared the former vice president’s experience with that of Buttigieg when he was mayor of South Bend, Indiana. The ad, and Biden’s stepped up criticisms of Buttigieg, came after Biden finished a distant fourth behind Elizabeth Warren, Buttigieg and Bernie Sanders in Monday’s Iowa caucus.

Asked if his criticisms were a sign of desperation, reminiscent of Hillary Clinton’s failed 2008 attacks on Obama in that presidential race, Biden told a reporter, “oh, come on, man” before tearing into Buttigieg.

Biden said he was merely responding to Buttigieg’s frequent criticisms of Washington politicians and the political sins of the past. Biden suggested that Buttigieg was saying that “somehow Barack Obama and I [presided over] some kind of disaster” while in office.

“He’s saying the problems we have now are because of the past. That’s what he’s saying. Let’s get that straight. Period,” Biden said. “The idea we have problems today, that Trump was elected because of the eight years of Barack Obama, I reject categorically.”

During the press conference, Biden denied that he was shooting off rhetorical rounds in the same kind of “circular firing squad” that he decried when he was a frontrunner.

“When you get attacked you gotta respond,” Biden said. “I kept my mouth shut for a long time.”