Tom said: "I would say no. For starters, we don't have the resources right now."

Robert said "Yeah, 2/3 of our combat forces are pinned down right next door in Iraq. Pretty ironic, no?"

Out of a miltary of 2 million, how does 130,000 become 2/3rds? Second, why would you describe the miltary in Iraq as "pinned down"?

The simple facts are that Iran is incapable of launching a conventional miltary attack against the Coalition forces in Iraq. They incapable politically, and if the political aspect was somehow was able to be overcome, they are miltarily incapable of launching a successful assault.
The US of course has no reason to invade Iran- except in possible raids against convert Iranian attacks. There are at least some elements within Iran which are attacking the Coalition and Iraqi forces. By launching a major invasion of Iran, US would be merely uniting the Iranians in their opposition. Our problem isn't that we are pinned down, but rather we have problem with it being very easy to attack Iran- we are being provoked, we are miltarily postioned so we can launch large number of raids into Iran- in other words "it's *too easy* to attack Iran", it might seem like a good idea to use our miltary power- whereas we should be more focused on using soft power.