I'll make three points, though:
1. They'd probably want to start with a massive air assault, which is probably doable, since Air Force isn't particularly busy in Iraq.
1a. Nuclear strike? You're probably familiar with this quote from reporter Philip Giraldi (American Conservative)
"The Pentagon, acting under instructions from Vice President Dick Cheney's office, has tasked the United States Strategic Command (STRATCOM) with drawing up a contingency plan to be employed in response to another 9/11-type terrorist attack on the United States. The plan includes a large-scale air assault on Iran employing both conventional and tactical nuclear weapons. Within Iran there are more than 450 major strategic targets, including numerous suspected nuclear-weapons-program development sites. Many of the targets are hardened or are deep underground and could not be taken out by conventional weapons, hence the nuclear option. As in the case of Iraq, the response is not conditional on Iran actually being involved in the act of terrorism directed against the United States. Several senior Air Force officers involved in the planning are reportedly appalled at the implications of what they are doing – that Iran is being set up for an unprovoked nuclear attack – but no one is prepared to damage his career by posing any objections."
http://www.informationclearinghouse.info/article9639.htmFor more details, there's a half-hour interview with Giraldi:
http://weekendinterviewshow.com/audio/giraldi.mp32. Michael Ledeen (check his latest writing at www.nationalreview.com) apparently believes there are forces within Iran that would pick up the fight and overthrow the government. How he can believe that, or if he really does, I've no idea, since flowers and candies didn't exactly materialize in Iraq. But this is what Neocons are saying all the way. See also references to "MEK" in Kurlantzick's piece.
3. Troops are in Iraq. Gen. Casey says numbers may be reduced by next spring. Bush gives Casey a dressing-down. Implication: the number of troops in Iraq will be reduced, but that doesn't mean they'll be comind home.
"The top American commander in Iraq has been privately rebuked by the Bush administration for openly discussing plans to reduce troop levels there next year, The Sunday Telegraph has learned. … Gen George Casey, the U.S. ground commander in Iraq, was given his dressing-down after he briefed that troop levels – now 138,000 – could be reduced by 30,000 in the early months of next year as Iraqi security forces take on a greater role."
http://www.antiwar.com/justin/?articleid=6938