What should be the US response if Israel carries out its threat to attack a US ship?

Israelis do not care who gets killed in their need to defend their "homeland". Americans have been blinded by lies of a biblical proportion, nature. Their control of western media will hide the true nature of any attack, they may call themselves victims (like when they murdered those humanitarians). Israel does not care, will kill anyone. America is too stupid, blind and lazy to notice.