After the Hillary Clinton campaign on Tuesday went after Sen. Bernie Sanders’ (I-VT) foreign policy background, the Vermont senator criticized Clinton for her 2002 vote in favor of the Iraq War.

“It is fair to say, that in terms of experience, Hillary Clinton was secretary of state for four years, so that gives her a lot of experience, no debate about that,” Sanders said in Iowa when asked about his foreign policy credentials, according to the Washington Post. “But there is a difference between experience and judgment. The most important foreign policy vote in the modern history of this country took place in 2002.”

Sanders told reporters that former Vice President Dick Cheney also had a lot of national security experience.

“I think on the crucial foreign policy issue of our time, it turns out that Secretary Clinton, with all of her experience, was wrong and I was right,” Sanders said, according to the Washington Post. “Experience is important. Dick Cheney had a lot of experience. A whole lot of people have experience but do not necessarily have the right judgment. I think I have the right judgment to conduct sensible foreign policy.”

Earlier on Tuesday, the Clinton campaign sent out a press release with a letter from 10 national security experts and former diplomats questioning Sanders’ knowledge on foreign policy.

“Over the past four debates, the subject of ISIS and Iran have come up a number of times. These are complex and challenging times, and we need a Commander in Chief who knows how to protect America and our allies and advance our interests and values around the world,” the experts wrote in the letter. “The stakes are high. And we are concerned that Senator Sanders has not thought through these crucial national security issues that can have profound consequences for our security.”