An influential politician who’s actually an enemy mole, turned while a prisoner of war, and now subverting America ... It’s the subject of Homeland, the hit cable series. Ironically, the program’s second season on Showtime unfolds exactly 50 years after a classic movie first named its theme.

The Manchurian Candidate premiered in October 1962. Since then the specific strain of ideological corruption has mutated, from communism to violent Jihadism, but the public remains fascinated with the concept of brainwashing – of Americans returning from captivity secretly beholden to foreign enemies. Now U.S. government records, many declassified after decades of secrecy, are finally revealing the real story behind the enduring meme.

The records describe Chinese spymasters assigning intelligence and propaganda missions to returning U.S. POWs and sending them home to a Soviet-linked support network of collaborators from Middle America to Eastern Europe.

Told to expect contact once back in America, the men were to “lay low for two or three years,” and “prepare the way in the United States for progressives to come later,” Army intelligence reported. Unlike the enemy’s robotic control of The Manchurian Candidate, influence over these real “Candidates” was much closer to the indoctrination and blackmail of Homeland. As to the ultimate effectiveness and extent of the program, much remains unknown. Just last year, the National Archives removed 60-year-old documents on this topic from public view, saying they’re still classified or may have “law enforcement sensitivities.” The CIA will not even confirm or deny it has such records. What has been uncovered tells a chilling tale, indicating reality was sometimes more disturbing than fiction. For example, the communists kept certain American prisoners forever to facilitate Soviet espionage and Cold War plotting, according to declassified files.

Brainwashing first gripped the national imagination during the Korean War from 1950-53, which pitted the United States, South Korea and their United Nations allies against North Korea and China, backed by the Soviet Union. For most of the war, Chinese commissars, working with Soviet advisors, controlled the publicly-known prison camps for Americans in North Korea, along with secret camps U.S. intelligence believed existed in China.

While many American prisoners in Korea behaved with distinction under appalling conditions, a large number collaborated with the enemy by informing on their fellows, writing propaganda statements and making detailed false confessions, including to germ warfare. Twenty-one of them, the so-called “Turncoats,” even chose to live in China after the war. These actions provided crucial ammunition to the “Hate America” campaign, as the Eisenhower White House called it, an orchestrated, high-stakes propaganda offensive then being waged by Moscow from the Third World to the United Nations.

At the time, military intelligence and the CIA scrambled to understand what could motivate American fighting men to turn on their country. Brainwashing appeared one possibility. The CIA launched its own mind-control experiments (ironically, these eventually involved more injurious techniques than many used by the enemy in Korea).

Hard answers finally arrived with the thousands of surviving Americans released from enemy camps in 1953. The Pentagon was ready with programs to interrogate and process the men, including the Army’s “RECAP-K” project (for men “recaptured” from Korea; the similar RECAP-WW project was soon added for the surprisingly large number of U.S. troops worldwide who - by defection, abduction or drunken escapade – landed in Soviet-bloc countries during the Cold War.)

Part of the plan was to root out prisoners “turned” by the enemy. Floating interrogations began on a troop ship headed home to the States. So-called “Progressives” (also known as “Pro’s,” or by the Chinese, “Good Students”) from the prison camps received most attention. Known collaborators, the Progressives had cooperated with their guards, sometimes at the cost of beatings from secret groups of anti-communist prisoners, known as “Reactionaries” (reactionary groups had their own nicknames, such as the “KTC" (Kill the Communists); “Federated American Hearts,” and “KKK.”) Thrashings of progressives actually continued on the troop ship; with no Chinese guards to protect them, some collaborators had to be segregated for their own safety.

Evidence from the returning Americans, according to intelligence reports and congressional hearings, disproved popular, and perhaps even hopeful, speculation about the motives for collaboration. The prisoners had not been drugged and brainwashed with secret, irresistible techniques. They were never under absolute psychological control of their captors. No secret triggers put them into a trance, such as the famous Queen of Diamonds in The Manchurian Candidate. In short, these troops had not been “brainwashed.”

Instead they had been subjected to the type of comprehensive indoctrination routinely employed by Soviet and Chinese officials against their own dissidents, along with German and Japanese POWs from World War II. The methods included isolation; sleep deprivation; compulsory ideological classes; threats; public- and self-criticism; endless “confessions;” exploitation of anger over U.S. racial discrimination; destruction of the chain of command; sophisticated psychological pressure; bribery and blackmail.