When does commenting about Israel crosses the threshold from legit criticism to anti-Semitism?

Recently, Israel’s defense minister, Ehud Barak said that all options are on the table when it comes to stopping Iran developing nuclear weapons. Translation, Israel may attack Iran’s nuclear facilities.

Iran is indeed developing nuclear weapons according to the international agency trying to monitor this. If Israel attacks, the belief is it would drag the US in that conflict that would have dire effect on the world economies. If Israel attacks it could be argued as justifiable pre-emptive self-defense.

On the other hand, even if Iran loads a nuclear warhead into a missile, would it actually be that dumb to fire at Israel, assuring its guaranteed destruction as well once Israel retaliates? ( or am I missing something here? )

Whatever Israel does these days, whether building more settlements, imposing blockades on Turkish ships and threatening to bomb Iran, they are subject to American comments, opinionating and criticisms. The US is a major financial supporter and ally of Israel and Americans have differing views on how to honor this alliance and what Israel should or should not do.