Rather than focusing on force structure, I think we should have a Two-War Production Strategy as a hedge against two wars. Deploying more troops than we can sustain is far more dangerous than having too few troops.
Proponents of this theory also assert that the United States is so bereft of the economic sinews of power and military capability that we must abandon our European allies, as well as long-time Middle Eastern security partners, and concentrate America’s military power solely on deterring a cross-strait invasion and defending Taiwan. From the standpoints of U.S. grand strategy and military analysis both assertions, however, are without merit.
I agree the Atlantic and Pacific must be defended. Europe is an economy-of-force front, but it is an important front.
Africa is lower down in priorities, but still a front.
And the Middle East still requires our attention to defend the gains we've made since America had to escalate its role and commitments during periods of major threats to stability and Western prosperity. This is the more visible part of the Global Troubles to keep jihadis from threatening America at home.
The two-front standard is interesting because in some ways it is misleading, as I explored in this post.
The standard is based on World War II when America focused on Germany while also going on offense against Japan, and committing lesser forces to deal with Italy.
Remember that America initially wanted to focus on Germany first while holding Japan at bay. But American production mobilization was so great that Japan could be dealt with as well. But even then America had to transfer lots of European Army divisions to the Pacific after defeating Germany in order to prepare to invade Japan.
Rather than build up our military size now on the assumption that war is looming, I'd focus on making our defense industry able to be the Arsenal of Democracy, which the Winter War of 2022 has exposed as hollow. Do that and make sure our troops and troop leaders get realistic training and benefit from other readiness measures. And for God's sake fix whatever is wrong with our senior leadership. That will make the force we have fully capable.
Readiness in materiel and leadership/training is hard to maintain but easy to squander.
If we repair our defense industrial base, readiness, and leadership first, expansion of our military forces to global war standards could be done when threats become more active and imminent. We could expand to the limits of our revived industrial capacity. If we reverse that we risk having an impressive-looking but hollow military. Which is a problem.
I have suspicions that the people who say we have to focus on China to the exclusion of all else are composed of too many people who have the Goldilocks Syndrome of seeking excuses to avoid dealing with the current military problem that Russia poses in order to save resources for the "real" threat that is looming.
UPDATE: This is timely. One of my most satisfying moments when I worked for the University of Michigan graduate library was when I was asked by a staff member in another division if Jomini's The Art of War was a significant work that should be retained. We really didn't know each other but he was aware of my military interest. I told him it should definitely be kept. I assume the Internet means such decisions are no longer reliant on such informal connections.
NOTE: TDR Winter War of 2022 coverage continues here.