This afternoon, Congress, for the first time since 9/11, reined in national security surveillance authorities. It’s a historic moment, and a great victory for civil liberties, privacy, and common sense – even if there is plenty more work to do. But what lessons should we draw from this accomplishment. In my view, elaborated here for the New York Review of Books, the principal lesson is that sunsets require sunshine. The USA Freedom Act would not have passed without the sunset, but it also would not have passed without Edward Snowden’s revelations about what the NSA was doing to all of us in our name. Indeed, Congress renewed Section 215, the authority the NSA relied upon for its program, seven times since 2001. It’s only the combination of sunsets and sunshine that can bring meaningful accountability and reform. That’s a lesson Congress needs to keep in mind as it engages in future battles over privacy and security. Read the full piece here.