After noting the ways in which Edward Snowden has vilified and idolized, Roger Cohen asks a more relevant and dispassionate question: what do we know now, that we would not have known at this time in the absence of Snowden’s whistleblowing?

We would not know how the N.S.A., through its Prism and other programs, has become, in the words of my colleagues James Risen and Eric Lichtblau, “the virtual landlord of the digital assets of Americans and foreigners alike.” We would not know how it has been able to access the e-mails or Facebook accounts or videos of citizens across the world; nor how it has secretly acquired the phone records of millions of Americans; nor how through requests to the compliant and secret Foreign Intelligence Surveillance Court (F.I.S.A.) it has been able to bend nine U.S. Internet companies to its demands for access to clients’ digital information.

We would not be debating whether the United States really should have turned surveillance into big business, offering data-mining contracts to the likes of Booz Allen and, in the process, high-level security clearance to myriad folk who probably should not have it. We would not have a serious debate at last between Europeans, with their more stringent views on privacy, and Americans about where the proper balance between freedom and security lies.

We would not have legislation to bolster privacy safeguards and require more oversight introduced by Senator Patrick Leahy, Democrat of Vermont and the chairman of the Judiciary Committee. Nor would we have a letter from two Democrats to the N.S.A. director, Gen. Keith B. Alexander, saying that a government fact sheet about surveillance abroad “contains an inaccurate statement” (and where does that assertion leave Alexander’s claims of the effectiveness and necessity of Prism?).

In short, a long-overdue debate about what the U.S. government does and does not do in the name of post-9/11 security — the standards applied in the F.I.S.A. court, the safeguards and oversight surrounding it and the Prism program, the protection of civil liberties against the devouring appetites of intelligence agencies armed with new data-crunching technology — would not have occurred, at least not now.

All this was needed because, since it was attacked in an unimaginable way, the United States has gone through a Great Disorientation. Institutions at the core of the checks and balances that frame American democracy and civil liberties failed. Congress gave a blank check to the president to wage war wherever and whenever he pleased. The press scarcely questioned the march to a war in Iraq begun under false pretenses. Guantánamo made a mockery of due process. The United States, in Obama’s own words, compromised its “basic values” as the president gained “unbound powers.” Snowden’s phrase, “turnkey tyranny,” was over the top but still troubling.

One of the most striking aspects of the Obama presidency has been the vast distance between his rhetoric on these issues since 2008 and any rectifying action. If anything he has doubled-down on security at the expense of Americans’ supposedly inalienable rights: Hence the importance of a whistleblower.