When Tim Edgar told his ACLU colleagues in early 2006 that he’d be leaving the organization to join the Office of the Director of National Intelligence, our reactions ranged from mute astonishment to outright dismay. It’s not at all uncommon for ACLU lawyers to go work in government. But to join the intelligence community during the Bush administration – the same gang that had brought us warrantless wiretapping, extraordinary rendition, and abusive watchlists – was really climbing into the belly of the beast.

It’s a good thing Tim was, and still is, thick-skinned enough to risk irritating former colleagues, first by charting his own path, and then by reflecting candidly on the full range of his experiences. “Beyond Snowden” is a unique and vital contribution to our ongoing debate about how best to ensure that powerful surveillance capabilities are constrained by laws and values.

Of course, I can’t pretend to be a neutral reader of a book that explores Edward Snowden’s role in setting in motion “the most significant reforms to surveillance…since those of the Church Committee in the mid-1970s,” and responds with an insider’s authority to the most common criticisms of Snowden’s actions. Chief among those is that Snowden should have pressed his concerns through internal channels, rather than sharing classified information with journalists. This particular critique has always puzzled me: internal channels may be effective when a government employee stumbles on an incidence of fraud or abuse unknown to superiors, but it’s ludicrous to suggest that there is an internal channel for complaints that a system of mass surveillance – authorized by the president, approved by the FISA court, and briefed to Congress – has been deployed in secret without the consent of the governed. Tim’s book provides another powerful rejoinder in the story of his own experience as “an authorized whistleblower for classified programs – a sort of official Snowden.” Unlike Snowden, Tim had “direct access to the officials who could have made surveillance reform a reality” – yet it was Snowden’s actions, not Tim’s years of internal advocacy, that led to widespread reforms.

This insight points to a broader irony. In the modern history of the national security state, there have been two periods of energetic oversight and reform, and both were initiated by spectacular acts of lawbreaking. The second, of course, is the subject of Tim’s book, but the first is less well-known. In 1971, a group of anti-war activists broke into an FBI field office outside Philadelphia, stole all the files, and mailed them to reporters at various newspapers, including the Washington Post, which published many of them over the strenuous objections of the FBI. The documents offered proof that the FBI was engaged in widespread domestic surveillance targeting anti-war groups, black student organizations, and other perceived dissidents from J. Edgar Hoover’s vision of America. One document referred without explanation to a program called “COINTELPRO.” Through litigation under the FOIA, journalists – and the public – learned what COINTELPRO was, leading to formation of the Church Committee and the formulation of the FISA regime.

In both of these episodes, extralegal activity was the critical impetus for overdue legal reforms. Tim’s book posits that excessive secrecy is in part to blame for this paradox. It also helps explain why activities that were consistently approved through classified oversight mechanisms were unable to survive public scrutiny. That doesn’t fully answer critics who insist that Snowden and the media took upon themselves decisions that had been entrusted by voters to government actors. But if reflexive and overbroad secrecy rules exclude the public from adequate knowledge of government conduct, and even from the legal justifications for that conduct, isn’t the argument that voters have entrusted these authorities to government actors substantially weakened and even circular?

This is an uncomfortable question, one of several that Tim is not afraid to grapple with. His book’s central question is how we can build oversight mechanisms that don’t depend on traumatic disruptions for their reinvigoration. The policy challenge is formidable:. Even Tim, who brought an ACLU lawyer’s skepticism to his work as an internal gadfly, found himself giving intelligence community leaders the benefit of the doubt. He confesses that he never considered it part of his job to scrutinize claims by his superiors that the NSA’s bulk collection of phone records had been effective in preventing terrorist attacks – claims that fell apart under scrutiny from post-Snowden investigations. His job was “to make sure privacy rules were followed….” His account is a powerful argument against the adequacy of internal agency protocols and Executive Branch self-policing.

The difficult project of establishing meaningful oversight would be aided by a deeper appreciation by all sides of the surveillance debates that their adversaries are generally acting in good faith. Too often it seems that we occupy parallel universes. In the first, the U.S. intelligence community operates in a framework so regulated and constrained that it should be the envy of the world, not the target of its scorn. No intelligence agency in the world can match our respect for rules and laws. In the second, the U.S. surveillance state has outgrown legal restraints and allowed its surveillance activities to be driven by technological capabilities. It developed and deployed a global system of mass surveillance without the knowledge or consent of the public, and it is sitting on massive databases of private information that constitute a genuine threat to free societies.

We should acknowledge the possibility that both of these pictures are largely accurate. The intelligence community is staffed by honorable public servants who have an abiding respect for the Constitution. And history gives us reason to be concerned that information collected for one purpose will likely be put to other purposes, particularly in the aftermath of a terrorist attack or other national trauma. We might even elect a president who has no regard for the rule of law.

Tim Edgar has lived in both of these parallel universes, and his book is a bridge between them. I hope it finds the large audience that it deserves.