At the same time, however, both the United States and the USSR did much to prevent the Cold War from escalating, as both countries knew how devastating a nuclear war would be. Truman, for example, kept the Korean War limited by refusing to use nuclear weapons against North Korea and China, aware that doing so would force the USSR to retaliate. President Dwight D. Eisenhower kept his distance from the Hungarian Revolution in 1956, knowing full well that the USSR would not tolerate interference in Eastern Europe. Likewise, the Soviet Union made sacrifices to keep the war “cold” by backing down from the Cuban missile crisis. Many Cold War historians believe that both countries worked hard to keep conflicts limited and used tacit signaling techniques to communicate goals, fears, concerns, intensions, and counteractions.