This excerpt from a RAND publication description is quite true:
Regional instability and conflict have often frustrated U.S. leaders' aspirations to pivot away from the burdens of military operations in the Middle East in order to shift resources to other parts of the world. As the U.S. Army looks across the Middle East and North Africa in 2018, it can anticipate and should be prepared for its current involvement there to extend into the future.
In 2003 (see pages 15-20), I argued that we faced an arc of crisis in that region that American troops in Europe could respond to better than deploying all the way from the continental United States without staging areas and troops already in Europe:
American bases in Europe already provide a stepping-stone for CONUS-based forces to use to deploy to trouble spots from Angola to central Asia. ...
The vast region from West Africa through North Africa, the Balkans, the Middle East, to Central Asia is a large area of potential crises[.]
And I noted that it was wise to stay in Europe in strength as a hedge against a revived threat to Russia.
Basically, I wanted XVIII Airborne Corps headquarters stationed in Europe with 5 of its combat brigades and prepositioned equipment for heavy brigades located there.
But Russia has revived as a threat so I'd rather put a heavy corps headquarters back in Europe with a parachute brigade, 3 heavy brigades, and a resurrected honest-to-God armored cavalry regiment (rather than the Stryker brigade that merely has the name), plus prepositioned brigade sets.
And a bonus to the RAND paper for noting that we tried to pivot away from the Middle East--which is what I said was the real purpose of the pivot to Asia.
Anyway, NATO has never been obsolete even as its primary usefulness has evolved over the decades depending what the major threat to Europe is at the moment--Soviets, the EU proto-empire, terrorism and unrest beyond their borders, or Russia.
Luckily, Russia is not the threat that the Soviet Union was despite Russian threats and bluster. The Russians are dangerous--as anyone with so many nukes is--but their conventional threat pales compared to the advantages geography and armed forces gave the USSR.
While Russia is still not a potential threat to more than the borderlands of NATO, NATO serves as a shield and sword to contest the arc of crisis.
