After Barack Obama was elected to his first term as President but before he took the oath of office, Vice-President Dick Cheney gave an exit interview to Rush Limbaugh. Under George W. Bush, Cheney was the architect, along with his legal counsel, David Addington, of a dramatic expansion of executive authority—a power grab that Obama criticized, fiercely, on the campaign trail, and promised to “reverse.” But when Limbaugh inquired about this criticism Cheney swatted it aside, saying, “My guess is that, once they get here and they’re faced with the same problems we deal with every day, they will appreciate some of the things we’ve put in place.”

I was reminded of that line during last week’s revelations about mass-surveillance programs administered by the National Security Agency. When Cheney said it, the remark struck me as cynical and self-serving. Now it seems prescient. Many observers have lamented Obama’s war on leaks—which has been distinguished by an unprecedented number of prosecutions—suggesting that there is some hypocrisy in a President who, having promised to roll back Bush’s “policy of secrecy,” has devoted his time in office to the merciless pursuit of whistle-blowers.

But the hypocrisy may run deeper than that: Obama built his political identity as a national leader on revulsion at the excesses of the Bush years. Yet, from warrantless wiretapping and torture to dodgy intelligence in Iraq, he knew the full extent of those excesses because of unauthorized disclosures to the press. Without leaks, Barack Obama might never have been elected to begin with.

Among those who took Obama the candidate at his word, and then found themselves sorely disappointed when he assumed office, was, it seems, Edward Snowden, a private contractor for the National Security Agency. Snowden, who gave a trove of classified documents to the Guardian and the Washington Post, said yesterday that he had watched, in dismay, “as Obama advanced the very policies that I thought would be reined in.”

Whatever your opinion of Snowden’s actions and motivations, his sense of betrayal by Obama is worth considering. The President was at pains, Friday, to insist that two programs revealed by Snowden were legal—that they were “authorized by Congress” and overseen by federal judges. But Obama’s Justice Department, like Bush’s, has not been above an opportunistic (and occasionally downright Procrustean) reading of particular statutes to permit whatever it is that the White House wants to do. Congress, while it has certainly obstructed Obama’s domestic agenda, now defers to him on many matters of national security—and, especially, surveillance—to a degree that flirts with abdication. And the Supreme Court has refused to consider the legality of the N.S.A.’s wiretapping programs on the tautological ground that no prospective plaintiff has standing to sue, because the relevant programs are so secret that any one citizen can only “speculate” whether or not he or she has been spied on.

“Nobody’s listening to the content of people’s phone calls,” Obama said, and this was supposed to be reassuring. But the first problem, as amply demonstrated by my colleague Jane Mayer, in a post last week, and by Shane Harris, at Foreign Policy, is that the metadata that is being collected is anything but trivial—in fact, it is often much more revealing than “the content” that Obama suggested was sacrosanct.

The second, and more pernicious, problem is that in talking about what is happening, rather than about what could happen, Obama is dodging the issue. “Trust us” is the age-old assurance of the executive branch. And for Obama, the professor of constitutional law, the appeal is more direct, and personal: “Trust me.” We see this in the debate (to the extent that there is any) about this Administration’s most dramatic executive license: drone strikes. White House advisers go out of their way to emphasize the personal care that Obama takes in making each life-and-death decision. He studies Saint Augustine and Aquinas, we are told, and consults with John Brennan, whom one former official described to the Times as a priest-like figure of “genuine moral rectitude.” Perhaps some people find this bespoke Presidential consideration comforting, but that kind of unreviewable lethal authority vested in a single individual is, in the end, disconcerting, however soulful and conscientious the individual in question may be.

What we have learned in recent days about surveillance is not so much that the government is constantly monitoring the activities of innocent civilians as that it is routinely collecting the kinds of data that would enable it to do so. “I, sitting at my desk, certainly had the authority to wiretap anyone, from you, or your accountant, to a federal judge,” Snowden told the Guardian. His credibility will no doubt come under attack in the coming days and weeks, and perhaps it should; there is still a great deal about this young man that we do not know. But when we are presented with this kind of statement from someone who, even on the lower rungs of the surveillance bureaucracy, had that degree of potential omniscience, it would be folly not to ask some serious questions about oversight, and about discretion.

The sad truth, which Dick Cheney seems to have understood, and which Obama the candidate may have underestimated, is that the accumulation of executive power is, to borrow a phrase from Charlie Savage, of the Times, a “one-way ratchet.” Particularly when it comes to national security, Presidential authority is easy to accumulate and very difficult to undo. In his book “Takeover,” Savage quotes a vivid observation by the Supreme Court Justice Robert Jackson, who warned that once established, a new executive prerogative has a tendency to lie around, “like a loaded weapon ready for the hand of any authority that can bring forward a plausible claim of an urgent need.”

President Obama and his supporters on both sides of the aisle in Congress will tell you that any abuses of these N.S.A. programs are “hypothetical,” and that may be true. But the technologies are like Jackson’s loaded weapon—one that may not have been misused so far, but that could be any day.

Photograph by Charles Ommanney/Getty.