Before the break of dawn on April 15, 1961, a squadron of eight B-26 bombers piloted by Cuban exiles roared down a Nicaraguan airstrip on a secret mission. The U.S. Central Intelligence Agency (CIA) and President John F. Kennedy hoped the Bay of Pigs Invasion would result in the overthrow of Cuban leader Fidel Castro. But the operation that unfolded over the next five days became one of the greatest military fiascoes in American history.

President Dwight D. Eisenhower had first sanctioned the covert CIA operation in 1959 to topple Castro, who had nationalized American industries and strengthened ties with the Soviet Union after leading a revolution that ousted the pro-American military dictator Fulgencio Batista.

The plan called for an initial air strike to wipe out Castro’s small air force, followed by the amphibious landing of 1,400 Cuban expatriates at the Bay of Pigs, an inlet of the Gulf of Cazones on the southern coastline of Cuba. The ex-pats had been trained by the CIA in Guatemala and Florida. Once the insurgents established a beachhead, a provisional government of exiled Cubans would fly there from Miami, declare themselves the country’s rightful leaders and invite the United States to send in troops to assist in the operation to depose Castro.

When the plan, codenamed Operation Zapata, was presented to John F. Kennedy just weeks after he took the oath of office, the newly inaugurated president ultimately gave it his approval. Jim Rasenberger, author of The Brilliant Disaster: JFK, Castro, and America’s Doomed Invasion of Cuba’s Bay of Pigs, doesn’t believe that military planners pressured the new president into making a decision against his better judgment. “I think Kennedy knew very well what he was getting into, but he was in a tough place,” he says.

During the 1960 presidential campaign, Kennedy had repeatedly called for American intervention in Cuba. “Incredibly, Kennedy got elected by outflanking Richard Nixon as an anti-communist hawk. He beat up the Eisenhower administration for allowing Castro to come to power and not doing anything about it. So he became president in large part because of his anti-communist rhetoric, and he didn’t want to look like a hypocrite or soft on communism.”

Even before the operation could be launched, however, Castro learned through his intelligence channels details of the American-backed plan. So did anyone with a subscription to the New York Times because on April 7, 1961, the newspaper published a page-one article reporting that “United States experts” were training an invasion force of Cuban exiles in Guatemala and Florida.

“I can’t believe what I’m reading! Castro doesn’t need agents over here. All he has to do is read our papers!” Kennedy snapped. Although the invasion would lack the element of surprise, neither the CIA nor the White House called it off.

Just hours after the initial strike on three Cuban airfields by the CIA-backed B-26 bombers on April 15, the operation began to encounter problems. The initial raid failed to destroy all of Castro’s air force, with six Cuban aircraft unscathed. “If the operation had any chance of success,” Rasenberger says, “the CIA planners knew the most important thing was to get rid of Castro’s air fleet. They could not have a beachhead invasion if the ships could be sunk.”

Having failed to wipe out the Cuban air force, the operation encountered further difficulty when a planned ruse backfired. One of the bombers that took off from Nicaragua landed at Miami International Airport with its pilot claiming to be a Cuban air force defector. CIA operatives, however, had painted the bomber to resemble one of Castro’s and riddled its engine cover with bullet holes to make it appear that it had survived combat.

The American hand in the operation, however, was quickly detected by reporters who noted the plane’s fresh paint job and the placement of machine gun barrels in the bomber’s nose and not mounted on the wings as on Cuban warplanes.

“Immediately the entire world knew they were CIA-backed pilots,” Rasenberger says. “Kennedy realized any illusion of plausible deniability was gone. He could no longer pretend the Americans weren’t behind it.”

The president responded on April 16 by cancelling a second round of bombings planned for the following day, which left Cuban air defenses intact for when the invasion force arrived in the Bay of Pigs the following morning. “The moment that Kennedy canceled the second round of bombings on Castro’s air fleet the operation was basically doomed, and everybody knew it,” Rasenberger says.

Things continued to go wrong as the American-backed fighting force attempted its amphibious landing under the cover of darkness. When studying reconnaissance photographs, CIA analysts had failed to spot coral reefs in the shallow waters of the Bay of Pigs that impeded the progress of landing craft and disabled a pair of boats.

In addition, one of the red signal lights carried by a frogman accidentally flickered offshore. When a pair of Cuban militiamen in a jeep spotted the light and pointed their headlights toward them, the frogmen opened fire with their rifles and machine guns, ruining the element of surprise.

Further difficulties came when Castro’s aircraft sank two supply ships that carried food, medical supplies and ammunition. An additional failure of a CIA reconnaissance team to spot a radio station on the beach allowed it to remain in operation during the invasion and broadcast details of the attack across Cuba.

With the invasion floundering, Kennedy refused to send in Marines stationed in Puerto Rico or a large naval force that stood at the ready outside Cuban territorial waters. However, he did relent in authorizing six unmarked Navy jets to provide air cover for one hour on the morning of April 19 for a squadron of B-26 bombers taking off from Nicaragua to strike Castro’s fighters. That also ended in disaster as the B-26s arrived an hour earlier than planned and found no escort cover, possibly because of a misunderstanding about the one-hour time difference between Nicaragua and Cuba. The mix-up resulted in the downing of two B-26s and the deaths of four Americans.

With the attack fizzling and more than 100 of its members already killed in action, the brigade of Cuban exiles surrendered. As Rasenberger notes, Kennedy immediately responded to the foreign policy debacle by deepening American involvement in another Cold War conflict that would become a costly intervention.

“The day after, on April 20, Kennedy ordered the Pentagon to look into ways to defeat communism in southeast Asia,” Rasenberger says. “Kennedy’s reaction to humiliation is basically to escalate the conflict with the Soviet Union. He felt he had to get a win and he looks to South Vietnam.”