The principle: it may make sense to start an arms race if you think you are going to win if you start now, provided that a nastier arms race is inevitable later.
My impression is that while there were some people who thought the Soviet Union would turn out to be troublesome, most people believed (either genuinely or as the result of wishful thinking) that capitalism and communism could coexist, and thus the nastier arms race later was not inevitable.
My impression is that while there were some people who thought the Soviet Union would turn out to be troublesome, most people believed (either genuinely or as the result of wishful thinking) that capitalism and communism could coexist, and thus the nastier arms race later was not inevitable.