President Obama and other defenders of the amassing of data insist that no individual conversation or transaction is ever examined without “court” approval, meaning a warrant from the Foreign Intelligence Surveillance Court. But the court authorizes the scrutiny of more Americans than foreigners, and it is no court in the customary sense: it operates entirely in secret. Its members are federal judges from around the country, any one of whom may authorize the opening of files. Lacking any real challenge to the evidence, they function more as grand jury than court. Mr. Obama has conceded that only a handful of warrant requests have ever been turned down (a few have been modified), a success rate he attributes to government restraint.

Yet most federal judges are predisposed to defer to executive claims of national security. They are generalists with little experience in evaluating intelligence, and they are reluctant to hamper government operatives sworn to defend the nation. The same reluctance is evident among members of Congress, who pose as watchdogs but melt when they hear appeals to patriotism from the managers of the intelligence services.

In theory, Americans are in the habit of resisting government intrusions on their rights of free speech and association. Accordingly we should be skeptical of such overweening exertions. But the data-hauling has gone on for years without real challenge. When asked whether the government could not simply log individual suspicious calls without amassing a national database, Gen. Keith B. Alexander, the head of the National Security Agency, said he was open to discussing that approach, though it might delay work in a crisis. A delay of hours? Days? Weeks? Did President George W. Bush or Mr. Obama ever ask the question?

What ought to compound our skepticism is the news that there is money to be made in the mass approach. We are learning that much of the snooping is farmed out to profit-seeking corporations that have great appetites for government contracts, secured through executives who enrich themselves by shuttling between agency jobs and the contractors’ board rooms. We have privatized what should be a most solemn government activity, guaranteeing bloat and also the inevitable and ironic employ of rebellious hackers like Mr. Snowden.

Where then can we find the skeptical oversight that such a radical challenge to our freedom demands? Presidents beholden to their own bureaucracies seem disinclined to play the skeptic or even to create an elite independent commission, like the Warren Commission, which examined the assassination of President John F. Kennedy, to assess the conflict between liberty and security and point the way to reasonable balance.

Despite the predilections of federal judges to defer to the executive branch, I think in the long run we have no choice but to entrust our freedom to them. But the secret world of intelligence demands its own special, permanent court, like the United States Tax Court, whose members are confirmed by the Senate for terms that allow them to become real experts in the subject. Such a court should inform the public about the nature of its cases and its record of approvals and denials. Most important, it should summon special attorneys to test the government’s secret evidence in every case, so that a full court hears a genuine adversarial debate before intruding on a citizen’s civil rights. That, too, might cost a little time in some crisis. There’s no escaping the fact that freedom is expensive.