What impact did this arms race have on the war

 The nuclear arms race was one of the most alarming features of the Cold War superpower competition between the United States and Soviet Union. Both sides rapidly expanded their nuclear stockpiles, but after two decades, each embarked on efforts to cut down its arsenal.

Explanation: The United States' use of nuclear weapons to end World War II led to a determined and soon successful effort by the Soviet Union to acquire such weapons, followed by a long-running nuclear arms race between the two superpowers. The Soviet Union conducted its first nuclear test in 1949

cruel, heartless

explanation:

"the attempts of the proletariat to rise above this abasement"