Originally Posted by
RollingWave
It gives them much more room to run for awhile anyway.
I think the problem you have to consider with this is that you must realistically assess the USA's ability that could be put into this. I think it's very fair to say that the US can't possibly commit to a large scale war effort in the mid east for any significant period (like, over a year or two MAX) and especially not if things aren't totally smooth sailing. With things already as feisty back home, even if they could get the US into a war (which Trump could. ) it'd be a huge political struggle every day to keep it going.
I personally prescribe to real politik thinking too, but if you think that way you must also assume every other player think that way too. If I'm China and Russia, and Saudi bloc with US backing goes to war with Iran with the intention of invasion and overthrow of regime. I'm DEFINITELY going to help Iran as much as I can without turning this into WW3. (so probably no direct troops but potentially a ton of air and weapons and logistics support. ) meanwhile, one must realize that Saudi's army is complete garbage and I don't care how much more advanced their weapon is to Iran, no one should doubt that in strait up one on one Iran would be in Riyadh within 6 months if not less (assuming Iraq is neutral . ) while Saudi's real backup (aside from the US obviously) is Egypt who's actual interest don't line up as much as you'd think with the Sauds. ( Egypt is actually increasingly going closer to China. who has a huge huge strategic investment in almost the entire African continent. )
If the US want to do this war WITHOUT directly getting involved too much, its going to end badly because the Sauds are complete paper tigers. if they are going directly involved it could get tight as the strategic position of Iran is pretty good, you may need to assume your ships can't sail into the Persian Gulf safely. you may need to assume suddenly J-20s and Su-35s mysteriously "piloted by Iranians" start shooting down a couple of your war planes or at least force you to be much more conservative in your air power use.
And really what do you gain if you succeed is the bigger problem... the Sauds conquer Iran? rather unlikely, the Sauds genocide Shia's? possible but probably create bigger problems down the line. a puppet state in Iran? unlikely to last very long . meanwhile, if the war ends and Iran is still standing strong, the US are in for a world of problems (granted, they could just pull out of it all and let EuroAsia- Africa sort it all out themselves, but then you have to live with all the problems of losing the world hegemony