Max Frankel writes: I envy the commentators who, after a few days of vague discussion, think they have heard enough to strike the balance between liberty and security. Many seem confident that the government is doing nothing more than relieving Verizon and AT&T and Facebook of their storage problems, so that government agents can, on occasion, sift through years of phone and Internet records if they need to find a contact with a suspicious foreigner. Many Americans accept assurances that specific conversations are only rarely exhumed and only if the oddly named Foreign Intelligence Surveillance Court allows it. Such sifting and warrants — in unexplained combination with more conventional intelligence efforts — are now said, by President Obama and his team, to have prevented several dozen potential terrorist attacks, with elliptical references to threats against New York City’s subways and stock exchange.

Even if true and satisfying, these assurances are now being publicized only because this huge data-gathering effort can no longer be denied. Whatever the motive for the leaks by Edward J. Snowden, they have stimulated a long-overdue public airing. Although the government’s extensive data-hauling activity was partly revealed by diligent reporters and a few disapproving government sources over the last seven years, the undeniable proof came only from Mr. Snowden’s documents. Until then, the very existence of the enterprise was “top secret” and publicly denied, even in Congressional hearings. Even now, the project remains a secret in every important respect.

As those of us who had to defend the 1971 publication of the secret Pentagon Papers about the Vietnam War have been arguing ever since, there can be no mature discussion of national security policies without the disclosure — authorized or not — of the government’s hoard of secrets.

How many thousands have access to these storage bins? Who decides to open any individual file and who then gains access to its content? Is there ever a chance to challenge the necessity of opening a file? And what happens to gleaned information that has no bearing whatsoever on terrorism?

Given the history of misused “secrets” in Washington, such questions are by no means paranoid. J. Edgar Hoover used F.B.I. investigations and files to smear the reputations of individuals — even to the point of intimidating presidents. Throughout the government, “security” monitors leaked personnel files to Congressional demagogues like Senator Joseph R. McCarthy to wreck the careers of officials and blacklisted citizens with claims of disloyalty. President Lyndon B. Johnson and other officials used secret files from the Internal Revenue Service to harass and intimidate political opponents. President Richard M. Nixon tried to use the C.I.A. to cover up his Watergate crimes.

Information that is gathered and managed in secret is a potent weapon — and the temptation to use it in political combat or the pursuit of crimes far removed from terrorism can be irresistible.