Chapter 2: The Emergence of a Global System of States, 1500-Today

Outcome:

The sanctions do cripple the Iranian economy. Very quickly food is in short supply. Other nations are unwilling to go against the US and supply Iran. The citizens of Iran bear the main brunt of the difficulties, much like during the sanctions against Saddam Hussein's Iraq in the 1990s. Civilian deaths rise quickly into the hundreds and then the thousands. Iran declares that if sanctions are not eased immediately, it will be forced to accelerate the war process and invade.

What do you do now?

Continue sanctionsSee how things pan out. Iran has postured a lot in the past, and the threat may fail to materialize. Choking the citizenry may put internal pressure on Iran to comply.
Send troops to IsraelSend the signal that the US is behind Israel and is willing to fight on Israel's behalf (without actually engaging Iran).
Invade IranIran has made it clear that it is not attentive to diplomatic signals. Only direct military confrontation will get the message across.
Reduce sanctions and lobby the UNRequest military support should Iran choose to act militarily.