I’m not sure the USA will need to do anything. Given Israel’s successful recent “secret” bombing of Syria’s nascent nuclear reactor, Iran will be wary to do much knowing that Israel will retaliate with full force. Frankly, I don’t think they want to give Israel (or the USA) any justification for destroying their own nuclear programs, which is what would happen (and then some) if Iran attacked.
It is well known that Iran prefers to use its proxy, Hezbollah, to harass Israel from the North. In essence, Hezbollah in Lebanon is like the Russian missiles placed in Cuba in 1963, only Hezbollah is actually firing its rockets and kidnapping Israeli soldiers.