2020 Democratic presidential candidate Pete Buttigieg said on the "Iowa Press" television program Sunday that Joe Biden's vote to authorize the 2003 invasion of Iraq is an example of "why years in Washington is not always the same thing as judgment," AP reports.

“He supported the worst foreign policy decision made by the United States in my lifetime, which was the decision to invade Iraq.”

— Pete Buttigieg

Why it matters: As he's risen in the polls, especially in Iowa, the 37-year-old mayor has faced an onslaught of criticism over his lack of experience compared to the other top 2020 candidates.

Buttigieg has countered that his experience has come in other forms — in the military, in the private sector, and as the mayor of a small town in the Midwest — and that an outsider's perspective is needed to fix the problems that plague Washington.

The big picture: Biden has already faced criticism on the left from Sen. Bernie Sanders for his Iraq War vote, but Buttigieg occupies the same moderate lane as the former vice president — in addition to being a veteran who is half Biden's age. How Biden manages to continue defending his decision to support the war could play out on the next debate stage.

Go deeper: Buttigieg picks up more than 200 foreign policy endorsements