When it comes to national security, there are two kinds of secrets. One is the strict military secret. Examples would include the design specifications of a new weapon or planned troop movements. Giving such secrets to an adversary may tip the military balance and is clearly damaging to national security. Most people have little trouble seeing those who give away such secrets—like Manhattan Project physicist Klaus Fuchs, who gave design details of the first atomic bomb to the Soviets—as traitors who should be punished.

The second kind of secret is what anthropologists call the “public secret.” These are denied yet known. Their ambiguous status as simultaneously public and secret torques them with psychological conflict. The concept of the public secret can best be grasped through examples from family life. It may be a public secret that a man is having an affair, but as long as his family does not confront him, the pact of silence allows everyone to behave as if he really does work late a lot at the office. It may be a public secret that a woman is an alcoholic, but as long as no one mentions the bottles stashed in odd places or the mysterious mood swings, public appearances can be maintained. As anyone familiar with such family situations knows, the consequences of saying publicly what everyone knows privately can be profound, forcing corrections in behavior or breaking families apart. Not infrequently, as Henrik Ibsen famously dramatized in his play An Enemy of the People, opprobrium attaches most harshly not to the transgressor, but to the person who tells the truth out loud.

It is not just families that have public secrets. Religious institutions do too, as we learned from the child abuse scandal in the Catholic Church. And states have public secrets. For example, as the political thinker Michael Ignatieff has written, in Argentina under the military junta that ruled from 1976 to 1983, it was a public secret that activists and radicals were quietly being abducted by the military, tortured, and killed. This policy, under which between 15,000 and 30,000 citizens disappeared, was not publicly announced, and wealthy elites who had a vested interest in not knowing felt confident in denying it. Still, it was widely known in the way that whispered things are known. Eventually the ambiguity of the public secret was resolved and the facts were made public thanks to the indefatigable activism of the group the Mothers of the Disappeared, who demonstrated weekly in the Plaza de Mayo in Buenos Aires, and a truth commission appointed by President Raul Alfonsin. While the Mothers of the Disappeared could be dismissed as crackpots, a state commission armed with official documents finally had to be believed. As Ignatieff writes, the truth commission stripped the public secret of its deniability, forcing it into the open and working “to reduce the number of lies that can be circulated unchallenged in public discourse.” He observes that “its work has made it impossible to claim, for example, that the military did not throw half-dead victims into the sea from helicopters.”

Often the state’s greatest rage is directed at those who reveal public secrets, not military secrets. Richard Nixon called Daniel Ellsberg “the most dangerous man in America” not because he shared military secrets with the Vietcong (he did not), but because in giving the Pentagon Papers to the New York Times (and thus the American people), he made it impossible to deny what many already suspected—that the US government had lied about the reasons for the Vietnam War and about progress in fighting it.

US national security officials have likewise been enraged by Bradley Manning, the US Army soldier who gave WikiLeaks 250,000 diplomatic cables and 500,000 Army reports. Although the Obama administration claims that Manning and WikiLeaks gave away military secrets, for the most part they caused embarrassment by revealing public secrets. Many Americans had long been sure that, military propaganda notwithstanding, some American troops in Iraq were prone to using violence indiscriminately, killing innocents, and enjoying the act of killing, but Manning’s release of the “collateral murder” video, shot from a US military helicopter, gave visceral and undeniable form to inchoate knowledge. Likewise, in 2011 there were few Tunisians who did not know that their government was corrupt, but the people did not rise up against their government until WikiLeaks revealed that the US ambassador had cabled that "Corruption in Tunisia is getting worse. Whether it's cash, services, land, property, or yes, even your yacht, President Ben Ali's family is rumored to covet it and reportedly gets what it wants."

Even before he was found guilty, Manning has been punished harshly. The United Nations special rapporteur on torture complained that Manning—held for months in solitary confinement, often naked, and deprived of sleep—had been subjected to “cruel, inhuman and degrading treatment in violation of Article 16 of the Convention Against Torture.”

Like Manning, Edward Snowden gave away a public secret, revealing that the National Security Agency does not just spy on foreigners, but in violation of the legal framework established after the Vietnam War, also harvests vast quantities of information on the communications of American citizens, including email messages, browsing histories, postal records, and telephone metadata. When public rather than military secrets are given away, the state always insists that military security has been damaged, so it should not surprise us that the Obama administration claims Snowden gave away military secrets that will help those bent on attacking the United States. But there is a reason the top leadership of Al Qaeda has communicated for years by personal courier, and it would be a terrorist or insurgent with a very short life expectancy who would communicate by cell phone or unencrypted email. Snowden’s real crime was to reveal incontrovertibly what some already guessed and others might prefer not to know: The US government has secretly created a massive apparatus of domestic surveillance on the edge of the law.

American leaders say they will avoid future Mannings and Snowdens by segmenting access to information so that individual analysts cannot avail themselves of so much, and by giving fewer security clearances, especially to employees of contractors such as Booz Allen Hamilton, where Snowden worked. This will not work. Segmentation of access runs counter to the whole point of the latest intelligence strategy, which is fusion of data from disparate sources. The more Balkanized the data, the less effective the intelligence. And, as Dana Priest and William Arkin make clear in their important book Top Secret America, intelligence agencies are collecting so much information that they have to hire vast numbers of new employees, many of whom cannot be adequately vetted. Since 9/11 the National Security Agency’s workforce has grown by a third, to 33,000, and the number of private companies it relies on for contractors has tripled to close to 500. The more people know your secrets, the more likely it is they will leak out.

But, in the final analysis, the reason there will be more Mannings and Snowdens is that so many American secrets are not strict military secrets but scandalous public secrets pertaining to ways the US national security state behaves that are at odds with national or international law, or in conflict with fundamental national values. Whether one condones what Snowden did or not, it is clear that he was motivated by a deep sense of indignation that his government was doing something profoundly wrong. "If you want a secret respected,” said Senator Daniel Patrick Moynihan, one of the country's greatest commentators on secrecy, “see that it's respectable in the first place."

Editor's note: This article was updated to reflect the verdict in the Manning trial.