"As president, I will defend this nation, but I will do it responsibly. I voted against the war in Iraq, and that was the right vote," Sanders says in the ad released Tuesday, which will air in Iowa and New Hampshire.
He goes on to call for an international coalition, led by "Muslim boots on the ground," to topple the Islamic State in Iraq and Syria (ISIS), and promises to "end the quagmire of perpetual warfare in the Middle East."
The Vermont senator's team released the ad after the Clinton campaign highlighted a letter from former government officials — and Clinton aides — who questioned whether Sanders has "thought through these crucial national security issues" and hit his "lack of a strategy for defeating ISIS" as "troubling."
The experts served in multiple presidential administrations in both military and diplomatic roles, but many have deep ties to Clinton, who previously served as secretary of State.
Attacks between the campaigns have become more frequent with less than two weeks before the Iowa caucuses. Sanders has sought to frame Clinton as beholden to Wall Street, and Clinton has targeted Sanders's records on gun control and healthcare, recently adding the foreign policy arrow to her quiver.