Now, with the two moderate Democrats just three percentage points away from each other in Iowa and New Hampshire, the first two early voting states that tee off the nominating contest in mere weeks, Buttigieg has gone on a rare offensive against Biden. The mayor has criticized the former senator’s Iraq War vote—a favorite line of attack from Sen. Bernie Sanders (I-VT), who was opposed to the effort—and changed his tone on Biden’s son Hunter, who has been the subject of a coordinated misinformation campaign from President Donald Trump.

“As I’ve said before, I don’t think it’s a smart strategy because those who have gone after the VP on the Democratic side have not lived politically to tell about it,” Antjuan Seawright, a Democratic strategist familiar with Biden’s early state operation in the South, told The Daily Beast.

One person directly familiar with Biden’s thinking framed it more broadly.

“The closer you get to voting, the more pot shots you take,” the insider said. “He’s seen his numbers go down. We’ve seen this with [Sen. Kamala] Harris up and down, Warren up and down, and Buttigieg. Campaigns and candidates at some point kind of can’t help themselves.”