The House and Senate intelligence oversight committees were established to provide a check against intelligence abuses run amok in the shadows. The Foreign Intelligence Surveillance Court was set up for the same reason. But in the decades since these institutions were created, they have morphed into entities that perform wholly different functions than those they were designed to perform. Instead of providing independent oversight of the secretive intelligence agencies, these institutions more often than not provide political cover for those agencies’ actions—actions just as unseemly as those that prompted the creation of oversight institutions in the first place. In short: The oversight institutions have failed.

NSA whistleblower William Binney suggests a core reason for this failure is the committees’ and court’s inability to verify information about the programs and operations they are responsible for monitoring:

There are no checks and balances. What we call an oversight group is a joke at best. Even Reggie Walton, the former head judge on the Foreign Intelligence Surveillance Court, shortly after the Snowden revelations started to break, came out in a CNN interview and said he and the court has a very limited capacity to verify anything NSA or CIA or FBI even tell them.

Well, I’m here to say he had no capacity to validate, because whatever they tell him, he can’t challenge. He can only make sure that the “i”s are dotted, the “t”s are crossed, and all the forms are filled out. He can’t challenge the data that they’re telling him. Nor can the Intelligence Committee, they don’t know either. All they do is go out to these intelligence agencies and get briefed by them; they get the story from those agencies, and that’s what they know. It’s all being done in secret, in computer rooms and things like that, in the back, in very isolated places inside these agencies.

The oversight bodies established in the 1970s to restrain the intelligence agencies have failed to fulfill that mission. As Binney says, “what we call oversight…is a joke at best.” There’s good reason to believe some of the reasons for this failure are political. But as the former NSA mathematician observes, even if members of the intelligence committees or the FISA court truly wanted to provide rigorous, independent oversight—as Oregon Democrat Ron Wyden clearly does—they would be hamstrung by their inability to verify what the agencies under their watch tell them about their secretive work. The work is happening in dark rooms full of computers, “in very isolated places,” Binney says. How could any congressional oversight body or court ever be sure that the agencies are telling them the truth, or giving them the whole story?

They can’t. And that’s one of the most central reasons why we must protect intelligence whistleblowers, those brave people who put their lives on the line to tell the public the truth about how shadowy government agencies spend our money in the dark. Sometimes whistleblowers are motivated by their disgust over government waste, fraud, and abuse. Other times insiders cannot bear to sit by and do nothing as their bosses tell the public things that they know are false. Edward Snowden has said he was motivated to act after he saw the director of National Intelligence, James Clapper, lie to congress about dragnet surveillance. That lie may never have gone unchallenged if Snowden hadn’t taken bold action.

Instead of putting our nation’s truth-tellers in prison—or banishing them to exile in foreign lands—we should thank them for their courage, and then find some of our own. We’ll need a lot of it to undo what’s been created in the shadows.