Why, it happened all the time when Jimmy Carter was in charge!
Wait a minute. No it didn't. Happened under Reagan and Papa Bush, though. Most of eastern Europe got liberated from the forces of the worker's paradise.
Clinton had a stab at cleaning up the Balkans, with decidely mixed results.
Gunboat diplomacy is enormously effective in a large section of the world. Doesn't work against Islamist fascists, though. But the gunboats themselves have some effect. Stubborn stains may require repeated treatments.
There's a remote possibility we could see a Prague 1968 scenario in Ukrania. Then it will get very interesting.
Oh, and by the way, the Ukraine - a.k.a the Ukrainain SSR - was a Soviet province that no longer exists as such. It's Ukrania now. Like it or not.
(Or Ukrainia, for a valid alternate spelling. But why bother with spelling flames when there's such wonderful and interesting things going on to talk about?)