The U.S. military can enforce whatever the administration orders it to. The U.S. Navy already has warships in the Black Sea. That said, it boils down to a question of the will vs the means.

The means are at hand, it's the will that's lacking. Obama has no stomach for an actual challenge, hence the reason he favors gold as his main game. He was too gawky and gay to play basketball in the hood, and thus he shifted over to the gayest game on the planet outside of badminton.

Putin on the other hand, fancies himself a sportsman in the same league as Ted Nugent, and still has his nuts attached.