Unlike OTL, the United States is slow out of the gate in the first few years of the Cold War and there is no Marshall Plan or Berlin Airlift. In short, America pushes itself back into isolationism until much later. By the time the US enters world affairs, President Adlai Stevenson finds a world dominated by Soviet influence.
Much of continental Europe has fallen, as well as parts of Africa and large swathes of Asia. The British Isles, Australia, Japan, France, and the Iberian peninsula have all escaped communist takeovers, but many pro-Western governments only have a tenuous hold on power.
Eventually an OTL NATO analogue is set up, with much more of a emphasis placed on defense agreements and alliances with Central and South American nations. As the 1960s dawns, the US faces an unfriendly world overall, forced to maintain a large standing military and stockpiles of nuclear weapons on hair trigger. If there is one bright spot, it is the fact that many scientists have been able to escape the ever-expanding Iron Curtain and thus the US has quite a large scientific and technological leap on the Soviets and other communists.
Thoughts?