CNN host Soledad O’Brien finally had an Inigo Montoya moment on Monday, and all it took was former Republican Senate candidate Christine O’Donnell misusing the word “Marxist.”

Granted, it’s not the first time O’Donnell, a longtime anti-abortion activist, has called the president or Democrats “Marxist.” She even used the term to describe her Democratic opponent, Chris Coons, drawing exclamation points across the conservative blogosphere. But when she rolled it out on O’Brien’s show Monday, describing the president’s public statements as “Marxist sound bites,” it was little more than a nonstarter.

“Why do you think they’re Marxist?” O’Brien asked. “I mean, you kind of throw the words socialist and Marxist around that are not necessarily, I think, anchored in definitions of socialism and Marxism. So give me the definition.”