There won't be any "ground war in Iran". And anybody who suggests otherwise should be ignored.
If there's a need to knock out Iran's nuclear capability, then we'll do it WITHOUT any 'boots on the ground'.
I agree that we can achieve the objective of setting Iran's nuke program back ten years without much in the way of ground conflict. Here and there we may need some eyeballs on the ground to make sure that the penetrators disrupted a cascade, but no need to drive on Tehran just yet.
Unfortunately, we aren't the only ones with a say in the matter.
There are a couple of moves Iran can make which will push us towards a ground war, a push from Mashad towards Herat, maneuvers to close the Hormuz Strait, a general program of state sponsored terrorism with a few spectacular successes, moves against the Kurds or even into central Iraq towards Baghdad, or oil fields near Amarah or Basra, airstrikes on US targets in the Gulf or Iraq, attacks against Israel, potentially even Dimona, etc.
The root of Iran's problems lie with the mullahs. Any plan that doesn't look hard at the possibility of taking them out, even if it means going through 10 Pasdaran divisions and at least the same number of RA, is dangerously naive. No law says a ground invasion of Iran has to happen, but ignore the possibility at your own risk.
Not that Iran's a tough nut anyway. Both wars with Iraq were decided in the first ten minutes. We ate KARI, the best IADS France and Russia had to offer in less than 5, and Tiger Song, China's finest, took about 7. Iran just started on an integrated air defense system this year, with us watching, and if you believe the folks who kicked Chalabi to the curb, reading the mail all along.
Between 4 and 6 Iraqi RGFC divisions stood up and went combat ineffective is 24-48 hours this time around, during a stop action sandstorm and a media invented...operational pause. Search JSOW. This is the army Iran fought to a draw for eight long years. I wouldn't be surprised to lose some naval assets, perhaps even temporarily suspend naval ops in the Gulf (which the media will flip out over, driving oil prices way up), but the outcome is never in doubt, no matter how far we have to go to end it. That's on the military side, naturally, the political after effects are anyone's guess. In the worst case, we let them live like Afghans for a couple decades, until they hungry for a little freedom and social order.
Bottom line, if we don't gotta, fine, if they force it, be ready for it, but it won't be the end of the world. Personally, I think it will go all the way. I don't see the wild eyes laying down till their military options are gone.