Am I missing something here? If Iran were to finally become nuclear, Israel is target #1, whether directly or by one of Iran's terrorist clients getting it. Israel hardly needs - or should be required to ask - the approval of the U.S. to address the problem.

Furthermore, it should be obvious to anyone who isn't in denial that Iran is hellbent on becoming nuclear. When it will happen is debatable but it will happen sooner or later. And then the stability of the entire region is compromised. Regime change may ultimately be what is needed. And one shouldn't be too quick to try and draw parallels between Iraq under Saddam Hussein and Iran under Ali Khamenei as some sort of argument against a possible war.