However growing up in the Cold War I felt that NATO essentially acted as a block against war in Europe
Had Truman decided to send troops to Korea instead of Europe as he did....perhaps history might have turned out a bit differently as NATO sans American Troops might not have been able to deal with Russia while the United States was engaged in a full fledge announced War with China.
It was a near thing as Truman had plenty of people wanting the Nationalist Chinese engaged in the Korean War by invading Mainland China thus assisting the United States and UN troops deal with the North Koreans and Chinese forces in Korea but Truman felt the Chinese were all but fully committed already and ultimately saw the Russians as the greater communist threat and that China was being contained by the Korean fighting. Sending American troops to Europe was seen as much a deterrent to Russia invading Japanese territory as much as it was beefing up NATO against a Russian attack by requiring Russia to keep major units in the west rather than moving them east where they could threaten Japan.