It’s the fiftieth anniversary of the Bay of Pigs, April 17-18, 1961, when a CIA-trained army of Cuban exiles were sent by President Kennedy to overthrow Fidel Castro. Their humiliating defeat showed the world that Cubans would fight to defend their revolution, especially against an invasion sponsored by the United States. But that’s not the lesson Kennedy learned from his first great defeat as president.

Kennedy had campaigned in 1960 promising to remove Castro from power. The defeat at the Bay of Pigs did not change his mind about that. Instead, he ordered the CIA to find other ways to get rid of Fidel—ranging from sabotage of the Cuban economy to assassination. And planning began for another invasion, one that wouldn’t make the mistakes of the Bay of Pigs.

As the 1962 mid-term elections approached, Republicans denounced what they called Kennedy’s “do-nothing” policy toward Fidel since the Bay of Pigs. Reagan, Goldwater and William Buckley led conservatives in arguing for a new invasion, doing it right this time—using American troops instead of Cuban exiles, with massive firepower and bombing. The Senate and House both passed resolutions authorizing the use of the US military in a new invasion.

The Cubans’ response was to persuade their Soviet backers to install missiles on the island as a deterrent against another American invasion. Three weeks before the mid-term election, CIA spy planes photographed the new missile sites, and the Cuban missile crisis began.

Historians and journalists almost always describe Kennedy the winner of a mano-a-mano faceoff with Nikita Khrushchev, praising the way his steely resolve and strategic flexibility forced the Soviet leader to fold his cards and withdraw the missiles. But that perspective is too narrow. Yes, Khrushchev agreed to remove the missiles, but only in exchange for Kennedy’s pledge not to invade Cuba.

Reagan & Co. were outraged by this concession. Instead of giving up the plans to overthrow Castro, they argued, JFK should have used the Soviet missiles in Cuba as a pretext for launching another invasion of the island. Kennedy’s agreement, they said, would leave Fidel in power for decades. They were right, at least about that part. The real winner of the Cuban missile crisis was not JFK but rather Fidel.

Kennedy thus needed another country where he could demonstrate his resolve to use US military force (and counterinsurgency tactics) to defeat communist insurgents. After being defeated twice in Cuba—first at the Bay of Pigs, then in the missile crisis—he turned to a new arena: he would prove his toughness in Vietnam.