Mayor Pete Buttigieg turned on Joe Biden in an interview in Iowa on Sunday when asked about the former vice president’s support of the Iraq war.

“This is an example of why years in Washington is not always the same thing as judgment,” Buttigieg said. “He supported the worst foreign policy decision made by the United States in my lifetime, which was the decision to invade Iraq.”

Buttigieg commented on the war during an interview with Iowa Press on Iowa Public Television, according to a transcript obtained by the Associated Press.

The South Bend mayor has been hesitant to attack Biden directly in the campaign, as the former vice president remains at the top of the 2020 Democrat presidential field.

In October, Buttigieg criticized Republicans for attacking Biden’s actions in Ukraine and his son Hunter’s lucrative board position at a Ukrainian energy company.

At the time, Biden was grateful.

I’m a friend of Pete Buttigieg,” Biden said. “By the way, he’s a really decent guy. I turned on the television this morning and he was defending my family against these outrageous, lying ads of the president of the United States of America. That’s a good man.”

But Buttigieg appears willing to remind voters of Biden’s past support of the war in Iraq, a key distinction for modern Democrats.

In the 2008 Democrat presidential primary, former President Barack Obama successfully weaponized then-Sen. Hillary Clinton’s support for the war in Iraq as a cause to doubt the more experienced senator.