We don't have any intention of invading Iran. It's a different situation than Iraq. There's already apparatus in place to take over if the mullahs have an "unfortunate accident." In Iraq we had to invade to avoid creating a power vacuum. In Iran you have an organized opposition already in place, ready to take over. You also have a regular military that can be active if the Revolutionary Guard has a bad day. I don't think there will ever be the need for one US boot to be on the ground in Iran.
The issue is not US boots in Iran. If all the possibilities are thought out so well, there wouldn’t be a bloody boot anywhere then, would it? My point is we shouldn’t force something that with support, evolves our way and wouldn’t become another Iraq or, remember Lebanon.