The real answer is that US admin are cowards. They want two things above all else: a) to continue their disastrous Iran policy; b) avoid a greater war involving Iran.
Israel holds the trump card here, as they can publicly blame the US' Iran policy for the catastrophe and they can attack Iran and initiate a wider war whenever they want.
My guess is Israel refrains from criticism and doesn't attack Iran directly because as long as they do so, they can defeat Iran's proxies Hamas and Hezbollah piece by piece as long as US holds Iran in check.
Mired in ideology and corruption, the US regime cannot take the initiative on anything.
Good post. But also don’t neglect to consider that Mossad may have given Israel plenty of blackmail material on US politicians. Corrupt and sleazy politicians are not only liable to be blackmailed by our enemies, they can also be blackmailed by our allies.