Second, Montenegro would add little to any alliance against us. Even bitter, dedicated Montenegrin enmity of America wouldn’t keep us up at night. Any real threat would require Montenegro to pair up with someone much stronger — say, Russia — and to serve as a base for their forces. Yet this, too, would have a limited impact on U.S. security.
Let’s imagine a worst-case scenario. Nuclear-tipped short-range ballistic missiles placed in Montenegro could make regional missile defense tougher and contribute to instability, but would not give Russia an unanswerable threat with which to control the area. Such missiles are right on Poland’s border, and the Poles have yet to fold. (It’s also unclear that the Russians would want to deploy such missiles to Montenegro. They didn’t deploy them near Poland for years.)
Advanced Russian air defenses and anti-ship missiles could complicate NATO operations in the area in the event of a general NATO-Russia war, but Montenegro would still be a diversion from the main fight. Russia would also be unable to resupply Montenegro in a war. It would have to go through the many NATO members between Montenegro and the rest of the world to get there. A Montenegro undefended by American troops is not a gateway to Russian dominance.