Tami asks, as a reaction to the casus belli issue, what exactly "victory" would be in a conflict with Iran and how it's possible with the enormous problems the U.S. Army is facing right now.
It's a good question. The answer is that "victory" can end up being subjective, and the perception of how to get there even more so. People disagree about how to achieve victory; one side may be right, another may be wrong, but there's still going to be disagreement.
In the case of Iran, the Powers That Be in DoD clearly still believe that victory is possible from the air, and from the sea. Thing is, it's only the U.S. Army that's truly bogged down in Iraq and Afghanistan. The other branches are, if anything, somewhat underutilized right now.
(Air and sea power is pretty useless in fighting an urban insurgency.)
Here's the strategic breakdown. The key issue with Iran is whether it can be cowed into capitulation, or humiliated into a domestic revolution. Either way, the Iranian nuclear threat is diminished: in the former case, the mullahs are disarmed enough that US (and Israeli) strategic preeminence in the region is unquestioned, and in the latter case, the theory is that more democratic, pro-Western forces than the Mullahs would succeed in a revolution, and the US (and Israel) retains regional strategic supremacy. Humiliation would provoke the revolution, because it would show how weak the leadership actually is, and others would seize the opportunity.
The American neoconservatives have always been of the opinion that this is possible, and that air power can do this, whether land-based (the Air Force) or sea-based (the Navy). Blow up enough of the infrastructure that the Mullahs depend on, and the people will revolt, because they don't hate the United States anywhere near as much as their government masters do, or as much as they hate said masters themselves. A revolution will take place again in Iran, but this time, it'll be a revolution by supposedly pro-western elements, such as Mujahedin-e Khalq (MEK), which they've been careful to avoid applying the "terrorist" label to. They'll then open up the country to American troops and American influence.
That's how the United States would, theoretically, win without ground power, and how they could win with their forces in Iraq still bogged down.
Of course, a lot could go wrong. There are a ton of assumptions there. I don't agree with a lot of them, principally the idea that bombing the crap out of Tehran would foment an anti-Mullah revolution instead of a "rally 'round the flag" effect. It's never been quite clear why they think this would be the case, beyond the most powerful Orientalism the world has seen since the sunset of the British Empire. It's contradicted by America's own experiences and any objective historical analysis of the region.
Nonetheless, Tami, that's how they think they'd win.
God help us all.