I believe Iraq was/is a success, let me just get that on the table. However, things could have been better. For instance, locals were allowed to keep one rifle per male in their home. It doesnt matter if its one rifle or 100 rifles, it's still bullets to fly.
My solution is outlawing weapons in Iran, after we invade, provided that it will involve boots on the ground. Failproof plan. If someone has a rifle or a weapon they die, that takes care of three things: 1 less Muslim in the world, 1 more living soldier, and no more "is he a threat?" cases.
Because the focus on Iran wouldn't be to topple the government and hold their hands for a while, I would say boots on the ground would not be necessary. Bombers and fighters 30,000 feet and US warships lining the coast is the best medicine for Iran. I'm not talking wimpy stuff, either.
The Muslim people, I have been told, respect power. That is what our military is. If we show them the full force what the US Navy and Air Force have to offer, the odds of them backing down would be far greater than just hitting select targets with smart bombs.