(lat) William I. Robinson, a professor of sociology at UC Santa Barbara, probably shouldn't have been surprised when he found himself in the news earlier this month. He had, after all, forwarded an e-mail to his students that juxtaposed images of Palestinians caught up in Israel's recent Gaza Strip offensive with Jewish victims of the Nazis. The e-mail included graphic photographs of dead Jewish children from the 1940s alongside similar photos from Gaza. In a cover note, Robinson called the images "parallel" and compared Gaza to the Warsaw Ghetto. The outcry built slowly. First, a few students complained; then, organized groups became involved. Two national Jewish leaders accused Robinson (who is himself Jewish) of anti-Semitism, and the university's Academic Senate opened an investigation and is considering disciplinary proceedings. Articles about the controversy have been published all over the world and have given rise to fundamental questions: Is it ever acceptable to compare Israelis to Nazis? When does criticism of Israel become anti-Semitism? And who should make these calls? The Times asks and answers a few questions to help frame the debate.