"Standing army" used to be an epithet, a sign that a society had lost its way. The best military we've ever had was the one we built from scratch for WWII. They curbstomped two actual "evil empires". Everything we've had since has been a pale imitation, not fit to wear the same uniform. That's because in WWII we were trying to win, and ever since then we've been trying to spend money.
If we demobilized, we'd probably never really need to remobilize. (What, are the Nazis going to rise again?) But if we did, we could.
> If we demobilized, we'd probably never really need to remobilize
This is a very 1990s/2000s point of view. We have a real global competitor now. China's military spending is rising faster than their fast-rising GDP. Some recent war games exercises suggest that the US could already be in losing position in a conventional war with China [1].
Not even our generals are stupid enough to get in a war with China. (Our politicians probably are, but they're not in charge.) They'd probably take all of our Pacific Islands, and they would definitely sink all our carriers. It will take a few years for the Pentagon to forget the asskickings we've received recently. They're searching for nations smaller and weaker than Syria; China is off the list completely. Even though we spend far more on the military than they do.
However, we don't have to get in a war with China. We owe them trillions of dollars. We're probably not going to start out by straight-up defaulting, but there are all sorts of things we could fiddle with to put the hurt on them. What are they going to do in response? Stop exporting us lots of crap? That would be good for American workers. Maybe they'll hack American firms' insecure shit more? Ditto.
We would live happier, healthier, and more prosperous lives if we stopped viewing every challenge through a military lens. Especially since our military is incompetent to achieve any goal through military action.
If we demobilized, we'd probably never really need to remobilize. (What, are the Nazis going to rise again?) But if we did, we could.