There are some, who want America to be able to practically dictate their positions, and bend other governments to the US’s will. The projection of power that the US participates in, keeps many things better for trade, and influence in almost all matters concerning the international community.
The US has all those aircraft carriers, for a reason. Same with bases around the world.
I personally think that the US would still be very “powerful,” without so much military presence around the world. Militaries, should be for defense of the homeland, mainly. I would be a fan of pulling most of our presence out of most foreign places. In large part because the US has no right, to play world police. In part, because we’re very selective/inconsistent, or bad at it…
The US gas geographical advantages, that almost no other country has. There is absolutely no threat, of a foreign military/enemy putting boots on actual US soil. And that is a great reason to show a more relaxed position.
Our biggest concern is Russia deciding to invade parts of Western Europe. But… That should really be up to those European nations, as far as building up a deterrence against Russia. If the US gave a timeline for leaving completely, the former NATO countries would be forced/wise to put their own resources into the issue. They could do it. Even if that meant selling off some of the US equipment currently there, to help them have time to bulk up their militaries, and form whatever alliances they feel would protect them the most.
US forces in South Korea, could be pulled as well. Let Japan help SK. North Korea doesn’t have the resources to really take any land. They have an old military, and very little oil, or needed supplies for a prolonged war. With US forces gone, tensions may ease up a bit even…