The problem for the US is that these are all big flat deserts, and Iran has most of the advantage because they control the mountains. So if the US has the low-lands, it's bad because Iran will pick at them from the mountains, but if the US give up the low lands, they're not gonna get them back later unless either Iran makes a big error, or the US has a lot more fighting power.
Maybe that's the point of starting the draft next year - to win back the land in Saudi Arabia that they're currently about to lose. Not to even try to fight Iranians in their own mountains...
