(CNN) How did Donald Trump defend his lewd and sexually aggressive comments against women in the second presidential debate? ISIS. It's perhaps the first time the extremist group that has waged terror across the globe has been evoked to answer a question about a hot mic sex tape. But ISIS wasn't the only global threat the presidential candidates tackled in their vitriolic back and forth that had both US audiences and non-Americans captivated. Here's the key moments in a debate that laid bare the candidates' stark foreign policy differences. Because ISIS Trump answered a question from Anderson Cooper about the vulgar language he was caught on tape using a decade ago with a rant about ISIS, mentioning the group at least five times.