In 2013, Edward Snowden leaked top-secret documents that forced the National Security Agency to become more transparent about the scope of its mass surveillance programs.

Surprisingly, the massive leak also made the NSA more effective in the ensuing years, according to Timothy H. Edgar. In his book Beyond Snowden: Privacy, Mass Surveillance, and the Struggle to Reform the NSA, Edgar claims Snowden's revelations represented an important first step toward addressing individual privacy concerns and updating severely outdated data collection procedures.

Edgar's career path gives him a unique perspective on digital surveillance and privacy. He went from an American Civil Liberties Union (ACLU) lawyer who argued against privacy violations to working with the CIA reviewing the U.S. government's most secret surveillance programs. He is now a senior fellow at the Watson Institute for International and Public Affairs at Brown University, and the academic director for law and policy in Brown's Executive Master in Cybersecurity program.

In the book, Edgar explains how and why the United States can keep Americans safe from security threats, while still protecting citizens' privacy. This excerpt is taken from Edgar's introduction, where he discusses how Snowden's leak forced the United States to reform its digital surveillance techniques.

Around the time Edward Snowden began working for the Central Intelligence Agency in 2006, I decided to leave my position as a lawyer for the American Civil Liberties Union in the hope I could make a difference by going inside America's growing surveillance state. Surprisingly, senior intelligence officials took a chance on hiring me in a unique new office safeguarding civil liberties and privacy. My job was to advise the director of national intelligence, who oversees the seventeen agencies of the U.S. intelligence community.

Before I joined the government, I had testified before Congress as an ACLU lawyer, arguing against expanded surveillance in the "war on terror." Since information on national security surveillance was secret, my arguments were based on hypothetical scenarios about how intelligence agencies might use their new powers.

After joining the government I learned the truth -- about bulk collection of data, the weakening of internet security, and other intrusive surveillance activities. The imaginative ways intelligence agencies were using their legal authorities exceeded the most alarming visions I had conjured up in my years as a privacy and civil liberties activist. The government was collecting immense volumes of data both inside and outside the United States, including data pertaining to Americans, creating serious privacy risks.

For the next seven years, I worked with a growing team of internal privacy watchdogs inside the intelligence community. We reviewed the U.S. government's most secret surveillance programs. Our job was to ensure these programs had a firm basis in law and included safeguards to protect privacy and civil liberties. As surprised as I had been by the breadth of surveillance, I was just as surprised by how seriously everyone inside the government took the rules that governed it. We brought the legally questionable surveillance policies of the Bush administration under the supervision of Congress and the judiciary, and devised new oversight mechanisms to ensure compliance with the rules. Our efforts put the U.S. government's mass surveillance programs on a stronger legal basis, helping the intelligence community weather the storm when these programs became public in 2013.

While I am proud of the work I did to keep intelligence agencies in bounds, it is fair to say my success in protecting privacy as an insider was limited. In retrospect, my focus on ensuring that the intelligence agencies were true to the complex and sometimes arbitrary legal rules that govern surveillance caused me to miss the broader impact of the U.S. government's programs on the privacy of all the world's data, and what this meant for the privacy of Americans. The rules that guided my work were designed to prevent "spying on Americans."

They were mostly written in the 1970s. They depended on geography and borders in a way that the internet and globalization had made largely obsolete. The digital data, communications, and personal lives of Americans now transcended national boundaries. Compounding the problem, the rules were based on analog technology.

They made distinctions that no longer made much sense between types of data, offering inadequate protection in an age of digital surveillance. Inside the intelligence community, these problems were well understood, and many shared my concerns.

To read more from Edgar's introduction, download/read the full excerpt.

Reprinted with permission from Beyond Snowden: Privacy, Mass Surveillance, and the Struggle to Reform the NSA, by Timothy H. Edgar (Brookings Institution Press, 2017).