My prediction: Iran will provoke the US with a missile attack on US forces. US will respond by sinking Iranian Navy, destroying Iran's Air Force on the ground and using new bunker busting bombs to take out Iran's nuclear facilities. President Obama then will be reelected by a landslide.

because it pushed the govt into high-spending projects for the war effort, creating jobs for the public. That too could work here however the US is already over-spending and another war will simply push it further towards insolvency. That's what #3 was getting at.

by protecting its vital energy interests and allies in the Gulf. Iran has threatened many times to disrupt it. The US operates in Intl Waters, not Iranian waters, and their presence is legal and justified. Iran has also made naval trips through the Suez to Syria, and to Venezuela. All legal though more of a provocation than an actual necessity.