>>936145043I don't know about your rule of thumb, I can only go by historical example:
>Iraq required roughly 500,000 people to invade and another million to pacify>Afghanistan required roughly 25,000 people to invade and 800,000 American soldiers alone to attempt to pacify>Iran currently has very roughly 3.5 times the population Iraq had at the beginning of the War on Terror and 4.5 times the population Afghanistan (and Iran also has a much larger geographic area)Even conservatively, a full scale invasion of Iran would require at least a million personal and any resistance like the US saw in Afghanistan, Iraq, or even Vietnam would require two million more. The current US military has around 1.4 million active personnel and 800,000 reserves, but even if all reserves are called up we have to take into account that significant numbers of US forces, particularly in the Navy and Air Force which account for over 900,000 by themselves, would remain around the world serving other roles. Continued recruitment could contribute to long term forces, but given it takes time for future soldiers to reach enlistment age it is often hard to keep recruitment up with attrition. As for foreign nations, many even among our allies have condemned the violence (on all sides) and called for diplomacy so it is unlikely many would support an armed regime change just like most stayed out of the Operation Iraqi Freedom.
Is a war against Iran theoretically winnable? Of course, although Vietnam, Afghanistan, and Ukraine provide some concerning counterexamples. Can a war against Iran be waged without the draft? Once again, it's possible (and as I've already said it's a moot point anyway). But it would absolutely strain American capabilities, critically reduce our overall security, and disrupt millions of American lives. It would not be small. It would be a full-scale war.