While calling for American leadership in the battle against the extremist proto-state (also known as ISIS or ISIL), Clinton twice said at the Des Moines event, hosted by CBS, that it "cannot be an American fight."
"I think what the president has consistently said, which I agree with, is that we will support those who take the fight to ISIS," Clinton said near the beginning of the debate. "But this cannot be an American fight, although American leadership is essential."
O'Malley quickly jumped in, saying he disagreed with the Democratic front-runner, and that it "actually is America's fight." Yet despite the difference in language, the former governor did little to distinguish how his approach would differ from Clinton's.
"America is best when we work in collaboration with our allies. America is best when we are actually standing up to evil in this world,"" O'Malley said. "And ISIS, make no mistake about it, is an evil in this world."
While making the same calls as his Democratic peers to work with other countries on the fight against ISIS, Sanders also used a question about ISIS to lay some of the international blame (and therefore responsibility) on the U.S. invasion of Iraq.
"I think (Clinton) said something like the bulk of the responsibility is not ours," Sanders said. "Well, in fact, I would argue that the disastrous invasion of Iraq, something that I strongly opposed, has unraveled the region completely and led to the rise of al-Qaeda and to ISIS.
Clinton, who voted for the invasion as a U.S. senator, was quick to note that the Western world — and the U.S. in particular — suffered attacks from radical jihadists well before the Iraq invasion.