- massive instability in the ME. Just a few men with shoulder fired missiles can disrupt oil shipments from the biggest oil producers
- the high chance of being sucked into a forever war. Iran can cause a lot of problems with limited resources and can rebuild. They have no reason to give up and the US might have to continue bombing indefinitely, or launch a ground invasion.
- the increased chance of nuclear war in the ME. This action assumes that Iran has no backup facilities, or will never have, to continue building a bomb. Having already suffered the consequences, Iran has no reason not to seek a bomb.