As the newly appointed Chief of Staff of the Army General Mark Milley has likely discovered by now, the United States has four armies—and he is in charge of the one with the bleakest budgetary and strategic future. The United States Army, which he heads, is responsible for the training and equipping of army forces that are to be assigned to one of our several regional and specialized combatant commanders—only some of whom are U.S. Army officers.

Then there is the United States Marine Corps, which feeds troops to the same commanders and has ground forces that are larger in numbers than the armies of most of our allies.

There is also the Army National Guard which, like the Marine Corps, now has its own representative on the Joint Chiefs of Staff—with the head of the National Guard Bureau recently gaining a seat on the JCS.

And finally, there is the U.S. Special Operations Command, one of the joint commands to which the U.S. Army supplies forces—and the only one that has its own acquisition authority and functions essentially as another service.

The U.S. Army’s budget is squeezed by the presence of the other armies. The Army National Guard lives off U.S. Army equipment and training facilities, but is never satisfied that it is getting enough. The favorite of Congress, the National Guard rarely loses a battle with the U.S. Army when the Army is foolish enough to attempt one.

The Marine Corps claims to be our frugal military force, providing, as it often says, a third of the nation’s ground power for only seven or eight percent of the defense budget. That, of course, is because it relies on the U.S. Army and Navy for so much of its equipment and support. And the U.S. Special Operations Command is the great bureaucratic black hole where service contributions, the U.S. Army’s included, go in never to return. In a time of tight budgets, the U.S. Army stands fourth in line among our armies.

For armies, size matters. The U.S. Army, sliding toward a likely post-GWOT total of 420,000 soldiers, will soon be roughly half the size it was at the end of Cold War. The Army National Guard at 350,000 soldiers is about the same size it was back in the good old Cold War days.

The Marines too have done well, heading down a bit to 185,000 (only about 10,000 less than they were at the end of the Cold War). The Special Operations Command is actually growing, having already surpassed 70,000 with nearly 40,000 of that number seconded from the U.S. Army. The Army is our reluctant but always available go-to-force for downsizing.

These competitors have the Army in box canyon, having staked out the strategic high ground in every direction. The Special Operations Command is our global anti-terrorism force, ready to conduct clandestine raids, and to train and guide locals in counter-insurgency techniques everywhere. The Marine Corps proudly proclaims itself to be our middle weight force, standing by for those small wars into which we inevitably stumble. And half ready as the nation’s strategic combat reserve for conventional wars is the Army National Guard—though it keeps busy in the meantime by helping us cope with floods and tornados on the home front.

What the Army is left with is preparing for two things: a large conventional war, which we all think is unlikely; or, occupying a country involved in a civil war (a task that we find the least desirable). The countries most able to challenge us conventionally—Russia, China, and North Korea—have nuclear weapons, so we aren’t exactly itching for that. And we have had our fill of the region offering the best opportunities to get involved in someone else’s civil war: the Middle East. The other armies have taken all the good, likely, and doable jobs.

Like our nuclear forces, the U.S. Army is becoming an afterthought; the Sunday punch that we once cared a lot about but don’t want ever to use again. It is Army boots that count, and we can’t think of a place we want them to go.