First of all, we should think a bit more than one step ahead and see a bit wider picture. And, of course, according the US Constitution, the safety of Americans should be more important for American decision-makers than safety of Israel (or, to be more specific, of the current Israeli regime).
Second, playing nuclear deterrence (hard power) and proxy terrorism (soft power) games are two quite opposite things. No one can have both of them, and no one have need in both of them simultaneously.
Third, Israel is a terrorist state, too.