NATO’s willingness to counter Warsaw Pact deployments of both conventional military and tactical nuclear forces; the decision to defend South Korea against the North’s aggression; the arming of the mujahedeen in Afghanistan to bleed Soviet occupation forces; and the decision to build a costly missile-defense system aimed both at negating the Soviet Union’s principal military investment and bankrupting its government. A second and very different school of thought emphasizes less what the West did and more what the Soviet Union was.