On February 2, 1953, in his first State of the Union address, President Dwight D. Eisenhower announced that the U.S. Navy would no longer shield the Chinese mainland against attack from Taiwan. Since the mainland was controlled by communists, while Taiwan was in the hands of Western-friendly nationalists, Eisenhower might seem to have been stating the obvious when he said, “We certainly have no obligation to protect a nation fighting us in Korea.” Yet not everyone agreed. The foreign secretary of Great Britain, an ally in the United Nations coalition in Korea, said that the move would have “very unfortunate political repercussions, without compensating military advantages.” A mainstream newspaper in India decried Eisenhower’s “specious and calamitous reasoning,” and said its “only result can be to extend the area of war.”

Such fears were legitimate because the temptation might well prove irresistible for Taiwan to attack a regime that was already fighting a war somewhere else. The conflict could easily have turned into a global struggle of communism against capitalism, with the added peril of nuclear weapons. That’s why the Navy had been keeping the peace in the first place.

Yet, from Eisenhower’s point of view, the two sides in Korea had been negotiating inconclusively for a year and a half as bloody fighting continued. His withdrawal of protection of Red China, combined with an increased commitment to arm and train South Korean forces, was meant to signal Joseph Stalin, seen as the string-puller behind communism worldwide, that the United States was losing patience.

What Eisenhower didn’t know was that Stalin’s physical and mental health were deteriorating rapidly. A month after Eisenhower’s speech, the Soviet dictator died of a stroke, and his death softened the communists’ resistance to making peace in Korea. In July, the two sides agreed to an armistice.

America’s get-tough policy had paid off. Still, as the nation chalked up another triumph over communism, it also took the first steps along a path that would reveal the limitations of that approach. On March 26, Eisenhower promised to support France in its fight against anti-colonial communist rebels in Vietnam. That commitment long outlived France’s involvement, entangling the United States in an unsuccessful war that would stretch on for two decades—and whose failure would continue to shape American foreign policy long after it ended, just as success in Korea had done.