The POWs of the Hanoi Hilton and the Code They Tapped Through the Walls

Every school should teach this fact: one of the most effective communications systems of the Vietnam War was built from knuckles, a wall and a grid of twenty-five letters. It had no wires, no batteries and no budget, and its operators were men in solitary confinement who were not supposed to be able to speak to one another at all.

That is the story of the American prisoners of war in North Vietnam. They were beaten, starved and isolated, and their captors were counting on isolation to break them. What the captors did not count on was the American military's habit of command, the Code of Conduct and the stubborn human need to say something to the man in the next cell. The Constitution makes the President the Commander in Chief and the people's elected branches the authors of war, but it is the discipline of the individual soldier that carries the republic's honor into a place where no law reaches. Here is how that discipline looked behind a French colonial wall in Hanoi.

The Prison and the Men

Hoa Lo prison in Hanoi was built by the French colonial rulers around the turn of the twentieth century to hold Vietnamese political prisoners. The North Vietnamese kept using it, and American airmen who were shot down over the North and captured were taken there. The first American pilot captured was Navy Lieutenant (junior grade) Everett Alvarez, shot down on August 5, 1964. By the end of the war, hundreds of Americans had passed through the system, mostly pilots and aircrew, and the Americans gave the main prison its famous nickname, the Hanoi Hilton, with the dark humor of men who were not going to give their captors the satisfaction of despair.

The prisoners were held in several locations and in sections of Hoa Lo that they gave names, from "Heartbreak Hotel" to "Little Vegas." The conditions ranged from bad to brutal, and in the early years the treatment included torture, designed to extract confessions and propaganda statements. North Vietnam had acceded to the Geneva Conventions of 1949, yet it insisted the airmen were criminals and not prisoners of war, which was its excuse for ignoring them. Hold on to that point, because it explains why the story is about more than courage. It is about what a free man does when the law that should protect him has been declared not to apply.

The Code That Held Them Together

The prisoners did not improvise their morality from scratch. They had one. In 1955 President Eisenhower issued Executive Order 10631 establishing the Code of Conduct for members of the armed forces, a six-article statement of what an American service member owes to the country and to comrades in captivity. Two of its articles became a working constitution inside the prison. Article IV says:

If I become a prisoner of war, I will keep faith with my fellow prisoners. I will give no information or take part in any action which might be harmful to my comrades. If I am senior, I will take command. If not, I will obey the lawful orders of those appointed over me and will back them up in every way.

And Article VI, the last, reads:

I will never forget that I am an American, fighting for freedom, responsible for my actions, and dedicated to the principles which made my country free. I will trust in my God and in the United States of America.

Notice what those articles do. They create a chain of command that survives the loss of everything else. In a camp where the guards want to treat each prisoner as an isolated individual with nobody to answer to, the Code says: there is a senior man, there are lawful orders, and you will back them up. The prisoners organized by rank and date of capture, set policy for resisting interrogation and passed it down through the walls. That structure is why a group of men subjected to years of pressure did not dissolve into a crowd of separate survivors.

The Tap Code

The captors forbade communication, so the prisoners built a way around the ban. The tool was a five-by-five grid of letters, a simple substitution grid. The alphabet is laid out in five rows of five letters, with the letter K left out and C standing in for it. A letter is tapped as two sets of taps: the first set gives the row, a pause, and the second set gives the column. An "A" is one tap, pause, one tap. An "E" is one tap, pause, five taps. A "W" is five taps, then two. Messages were tapped on walls with knuckles, a cup or a coin, and relayed from cell to cell, tapped on pipes, and passed along by sweeping and coughing in patterns.

Air Force Captain Carlyle Harris, shot down on April 4, 1965 and imprisoned at Hoa Lo, is the man generally credited with introducing the code to the prisoners there. Air Force accounts say he recalled it from survival-school training, where the instructors described a tap code that British prisoners had used in the Second World War, and he taught it to his cellmates. From there it spread through the prison. A conversation could be slow, but it could cover anything: names, medical needs, orders from the senior officer, a prayer, a joke. The usual sign-off was GBU, tapped for "God bless you."

Think about what that means. A man alone in a concrete cell, in pain, with no certainty that anyone is alive on the other side of the wall, taps out three letters asking for God's blessing on a stranger. Freedom of conscience does not exist in a vacuum. It exists in the choices of individuals who refuse to be told that they are alone.

The prison's guards did not like it and punished it, which is why the taps grew quieter and the codes more elaborate. The prisoners used the network to pass along names, orders and rules for resisting interrogation. The point of the plan was not to promise that nobody would break, but to prevent a broken man from believing he was finished. Americans do not leave their own behind, and that includes in the cell next door.

The Man Who Blinked TORTURE

On May 2, 1966, North Vietnamese authorities staged a televised interview with a captured Navy officer, Commander Jeremiah Denton, intending to show a contented prisoner to the world. Denton, who had been shot down on July 18, 1965, answered the questions in the stilted, loyal-sounding language his captors expected. But he knew the cameras were on his face, and he had noticed the bright lights bothered his eyes. So he blinked, and the pattern he blinked was Morse code, spelling out one word: T-O-R-T-U-R-E.

The pattern was recognized, and the message confirmed to the outside world what the prisoners were enduring, through a channel their captors had not thought to censor. It is difficult to improve on that as an example of a free man's wit. The state that made the film controlled the room, the questions, the lights and the editing, and a man held in its power sent his country the truth with his own eyelids.

Denton returned in 1973, and on arrival at Clark Air Base in the Philippines he said: "God bless America." He later served in the United States Senate from Alabama. The first public words of a man freed after years in a cell were a blessing on the country, and nothing in the record suggests he considered it a political remark.

The Leader: Stockdale

Vice Admiral James Stockdale was shot down on September 9, 1965, and became the senior naval officer among the prisoners. He held leadership responsibility in some of the harshest conditions, and he is best remembered for a principle he insisted on: that the prisoners should resist as a body and stay loyal to each other. When he learned that his captors intended to use him for propaganda, he injured himself so badly that he could not be presented to the cameras, which made clear that the price of using him would be higher than they wanted to pay. He was held in a section of the prison where the senior leaders were kept in isolation.

For this, and for his conduct as senior officer among the prisoners, President Gerald Ford presented him the Medal of Honor on March 4, 1976. The medal is the nation's highest military decoration, and its citation language tells the story of a man who put the group first. If you want to read how such citations are written, see What the Medal of Honor Is, Who Awards It and How a Citation Is Written and Five Medal of Honor Citations Read Closely and What Each One Asks of Us.

I would add one comparison. Another American in the prison, Navy Lieutenant Commander John McCain, was offered early release in 1968 because of who his father was, and he refused, because the Code of Conduct, in Article III, says "I will accept neither parole nor special favors from the enemy," and the established rule was that men would be released in the order they were captured. Whatever one thinks of anyone's later career, the refusal is a matter of public record and it is the Code in action.

The Founding Echo

The Declaration of Independence lists the crimes of George III, and one of them is oddly relevant. The King, it says, made citizens taken captive on the high seas "bear arms against their country" and become "the executioners of their friends and brethren." The Founders understood that treating a captured citizen as a tool, to be made to speak or act against his own country, is a species of tyranny. The Hanoi propaganda films tried to do the same thing in a modern form: make Americans say what the state wanted said.

The prisoners' resistance was the answer, and it was an answer the Constitution's authors would have recognized. A republic's citizens carry its principles inside them. When the rule of law is suspended around them, they bring the rule with them. That is why a society based on the consent of the governed produces people who can organize themselves under a code in a prison: they have been practicing self-government their whole lives.

The Strongest Objection

The strongest objection goes like this. The Vietnam War was a mistake, fought with confused aims and unclear authority, and so celebrating the men who endured it risks celebrating the war. A thoughtful person may hold the view, and many veterans do.

The answer takes three points.

1. The honor belongs to the conduct, not the policy. A soldier does not choose the war. The Constitution gives Congress the power "To declare War" in Article I, section 8, clause 11, and makes the President Commander in Chief in Article II, section 1. The men in the cells were carrying out orders from the civilian branches. Praising their courage does not endorse every decision made above them.
2. Criticizing the policy is the citizen's job, and it was done through the Constitution. Congress passed the War Powers Resolution over President Nixon's veto on November 7, 1973, a few months after the prisoners came home, to restore the legislature's role in sending Americans to fight. That is the proper conservative response to a war fought without clear authorization: restore the structure. It is not to blame the men who were sent.
3. The prisoners' own conduct is evidence of a different kind. They did not ask for sympathy and they did not ask for credit. They kept faith with each other under unimaginable pressure. A society that cannot honor that, because it disagrees with a policy, is a society that has lost the ability to tell the two apart.

Operation Homecoming

The Paris Peace Accords were signed on January 27, 1973, and under them the prisoners were released in stages. The operation, called Operation Homecoming, began on February 12, 1973, when the first group of prisoners left Hanoi, and ran until the end of March. In all, 591 American prisoners came home. The released men were flown to Clark Air Base in the Philippines before returning to the United States, and the releases went largely in the order of capture, in keeping with the principle McCain had insisted on.

The home they came back to was divided over the war, and the country did not always welcome returning veterans the way it should have. The prisoners' return was one of the few moments of national unity from that era. The POW/MIA flag, flown with the Stars and Stripes at many public buildings, remains a reminder of the Americans who did not come home, and the story of the flag itself is in Old Glory's Rules, What the Flag Code Says and Why Most of Us Break It. You can also read the national flag page at the flag guide.

For the policy follow-through, see Veterans Should Carry Their Health Care Dollars the Way They Carry the GI Bill and Seven Myths About Veterans That Shape Bad Policy, and the Facts.

What We Should Take From It

Three lessons, briefly. First, free men organize themselves, and they do it by rule and by rank, not by chaos. Second, a code of conduct is only useful if people believe it before the crisis, which is why we should teach it. Third, the truth survives in the smallest channels. A blinked word, a tapped letter, a whispered name: those carried more weight than a hundred staged films.

The prisoners did not leave behind a doctrine or a monument. They left a lesson in how to keep faith when no one is watching.

The case in brief

1. American prisoners in Hanoi kept their chain of command alive under the Code of Conduct, which Eisenhower established in 1955 and whose Article IV tells prisoners to keep faith with each other and obey the senior man.
2. The tap code, a five-by-five grid of letters tapped on cell walls, carried names, orders and prayers through a system designed to isolate every man.
3. Jeremiah Denton's blinking of T-O-R-T-U-R-E on a 1966 television interview and James Stockdale's leadership, which earned him the Medal of Honor, show free men outthinking a state that controlled everything but their conscience.
4. Honoring prisoners does not endorse every policy that sent them, and the proper response to an ill-defined war is to restore the Constitution's structure, as Congress tried with the War Powers Resolution in 1973.
5. Operation Homecoming brought 591 Americans home beginning February 12, 1973, largely in the order of capture.

What you can do: learn the six articles of the Code of Conduct, then ask a veteran in your community or at your local post whether you can help with a veterans' event or a service project.