As an American, you should be against this. We've already got a perfectly good defensive treaty with them that would compel us to act. Tripwire troops are only necessary if you don't believe the other party would honor the treaty, which is a perfectly reasonable stance for Latvia to have but I'd hope my fellow Americans wouldn't be so grim about that.

Permanently stationing troops there is only a cost burden to the American tax payer. It does advance American imperialism to have Latvia surrender some of their sovereignty to us, but that isn't exactly a noble goal. And certainly it doesn't materially improve the lives of the average American citizen.

> Americans are suddenly much more popular in Europe again

If you're concerned about hearts and minds, more bases is certainly not a good thing. American military personnel tend to be wildly unpopular in the surrounding areas, actively building resentment.