It has nothing to do with endangering national security (ignore the bleating of far too many corporate journalists who simply repeat talking points from their intelligence sources) but the profound shame of US hegemony being challenged and revealed.
Here’s Henry Farrell and Martha Finnemore in Foreign Affairs:
The U.S. government seems outraged that people are leaking classified materials about its less attractive behavior. It certainly acts that way: three years ago, after Chelsea Manning, an army private then known as Bradley Manning, turned over hundreds of thousands of classified cables to the anti-secrecy group WikiLeaks, U.S. authorities imprisoned the soldier under conditions that the UN special rapporteur on torture deemed cruel and inhumane. The Senate’s top Republican, Mitch McConnell, appearing on… Meet the Press… shortly thereafter, called WikiLeaks’ founder, Julian Assange, “a high-tech terrorist.”
More recently, following the disclosures about U.S. spying programs by Edward Snowden, a former National Security Agency analyst, U.S. officials spent a great deal of diplomatic capital trying to convince other countries to deny Snowden refuge. And U.S. President Barack Obama canceled a long-anticipated summit with Russian President Vladimir Putin when he refused to comply.
Despite such efforts, however, the U.S. establishment has often struggled to explain exactly why these leakers pose such an enormous threat. Indeed, nothing in the Manning and Snowden leaks should have shocked those who were paying attention. Former Defense Secretary Robert Gates, who dissented from the WikiLeaks panic, suggested as much when he told reporters in 2010 that the leaked information had had only a “fairly modest” impact and had not compromised intelligence sources or methods. Snowden has most certainly compromised sources and methods, but he has revealed nothing that was really unexpected. Before his disclosures, most experts already assumed that the United States conducted cyberattacks against China, bugged European institutions, and monitored global Internet communications. Even his most explosive revelation — that the United States and the United Kingdom have compromised key communications software and encryption systems designed to protect online privacy and security — merely confirmed what knowledgeable observers have long suspected.
The deeper threat that leakers such as Manning and Snowden pose is more subtle than a direct assault on U.S. national security: they undermine Washington’s ability to act hypocritically and get away with it. Their danger lies not in the new information that they reveal but in the documented confirmation they provide of what the United States is actually doing and why. When these deeds turn out to clash with the government’s public rhetoric, as they so often do, it becomes harder for U.S. allies to overlook Washington’s covert behavior and easier for U.S. adversaries to justify their own.…
Few U.S. officials think of their ability to act hypocritically as a key strategic resource. Indeed, one of the reasons American hypocrisy is so effective is that it stems from sincerity: most U.S. politicians do not recognize just how two-faced their country is. Yet as the United States finds itself less able to deny the gaps between its actions and its words, it will face increasingly difficult choices — and may ultimately be compelled to start practicing what it preaches.
Hypocrisy is central to Washington’s soft power — its ability to get other countries to accept the legitimacy of its actions — yet few Americans appreciate its role. Liberals tend to believe that other countries cooperate with the United States because American ideals are attractive and the U.S.-led international system is fair. Realists may be more cynical, yet if they think about Washington’s hypocrisy at all, they consider it irrelevant. For them, it is Washington’s cold, hard power, not its ideals, that encourages other countries to partner with the United States.…
Of course, the United States is far from the only hypocrite in international politics. But the United States’ hypocrisy matters more than that of other countries. That’s because most of the world today lives within an order that the United States built, one that is both underwritten by U.S. power and legitimated by liberal ideas. American commitments to the rule of law, democracy, and free trade are embedded in the multilateral institutions that the country helped establish after World War II, including the World Bank, the International Monetary Fund, the United Nations, and later the World Trade Organization. Despite recent challenges to U.S. preeminence, from the Iraq war to the financial crisis, the international order remains an American one.
This system needs the lubricating oil of hypocrisy to keep its gears turning. To ensure that the world order continues to be seen as legitimate, U.S. officials must regularly promote and claim fealty to its core liberal principles; the United States cannot impose its hegemony through force alone. But as the recent leaks have shown, Washington is also unable to consistently abide by the values that it trumpets. This disconnect creates the risk that other states might decide that the U.S.-led order is fundamentally illegitimate.…