Jane Mayer writes:

On June 13th, a fifty-four-year-old former government employee named Thomas Drake is scheduled to appear in a courtroom in Baltimore, where he will face some of the gravest charges that can be brought against an American citizen. A former senior executive at the National Security Agency, the government’s electronic-espionage service, he is accused, in essence, of being an enemy of the state. According to a ten-count indictment delivered against him in April, 2010, Drake violated the Espionage Act—the 1917 statute that was used to convict Aldrich Ames, the C.I.A. officer who, in the eighties and nineties, sold U.S. intelligence to the K.G.B., enabling the Kremlin to assassinate informants. In 2007, the indictment says, Drake willfully retained top-secret defense documents that he had sworn an oath to protect, sneaking them out of the intelligence agency’s headquarters, at Fort Meade, Maryland, and taking them home, for the purpose of “unauthorized disclosure.” The aim of this scheme, the indictment says, was to leak government secrets to an unnamed newspaper reporter, who is identifiable as Siobhan Gorman, of the Baltimore Sun. Gorman wrote a prize-winning series of articles for the Sun about financial waste, bureaucratic dysfunction, and dubious legal practices in N.S.A. counterterrorism programs. Drake is also charged with obstructing justice and lying to federal law-enforcement agents. If he is convicted on all counts, he could receive a prison term of thirty-five years.

The government argues that Drake recklessly endangered the lives of American servicemen. “This is not an issue of benign documents,” William M. Welch II, the senior litigation counsel who is prosecuting the case, argued at a hearing in March, 2010. The N.S.A., he went on, collects “intelligence for the soldier in the field. So when individuals go out and they harm that ability, our intelligence goes dark and our soldier in the field gets harmed.”

Top officials at the Justice Department describe such leak prosecutions as almost obligatory. Lanny Breuer, the Assistant Attorney General who supervises the department’s criminal division, told me, “You don’t get to break the law and disclose classified information just because you want to.” He added, “Politics should play no role in it whatsoever.”

When President Barack Obama took office, in 2009, he championed the cause of government transparency, and spoke admiringly of whistle-blowers, whom he described as “often the best source of information about waste, fraud, and abuse in government.” But the Obama Administration has pursued leak prosecutions with a surprising relentlessness. Including the Drake case, it has been using the Espionage Act to press criminal charges in five alleged instances of national-security leaks—more such prosecutions than have occurred in all previous Administrations combined. The Drake case is one of two that Obama’s Justice Department has carried over from the Bush years.

Gabriel Schoenfeld, a conservative political scientist at the Hudson Institute, who, in his book “Necessary Secrets” (2010), argues for more stringent protection of classified information, says, “Ironically, Obama has presided over the most draconian crackdown on leaks in our history—even more so than Nixon.”

Describing Drake’s concerns that the NSA was showing a flagrant disregard for the constitutional rights of US citizens, Mayer writes:

Drake says that in the Air Force, where he learned to capture electronic signals, the FISA law “was drilled into us.” He recalls, “If you accidentally intercepted U.S. persons, there were special procedures to expunge it.” The procedures had been devised to prevent the recurrence of past abuses, such as Nixon’s use of the N.S.A. to spy on his political enemies.

Drake didn’t know the precise details, but he sensed that domestic spying “was now being done on a vast level.” He was dismayed to hear from N.S.A. colleagues that “arrangements” were being made with telecom and credit-card companies. He added, “The mantra was ‘Get the data!’ ” The transformation of the N.S.A., he says, was so radical that “it wasn’t just that the brakes came off after 9/11—we were in a whole different vehicle.”

Few people have a precise knowledge of the size or scope of the N.S.A.’s domestic-surveillance powers. An agency spokesman declined to comment on how the agency “performs its mission,” but said that its activities are constitutional and subject to “comprehensive and rigorous” oversight. But Susan Landau, a former engineer at Sun Microsystems, and the author of a new book, “Surveillance or Security?,” notes that, in 2003, the government placed equipment capable of copying electronic communications at locations across America. These installations were made, she says, at “switching offices” that not only connect foreign and domestic communications but also handle purely domestic traffic. As a result, she surmises, the U.S. now has the capability to monitor domestic traffic on a huge scale. “Why was it done this way?” she asks. “One can come up with all sorts of nefarious reasons, but one doesn’t want to think that way about our government.”

[Bill] Binney [former head of the NSA’s Signals Intelligence Automation Research Center, or SARC], for his part, believes that the agency now stores copies of all e-mails transmitted in America, in case the government wants to retrieve the details later. In the past few years, the N.S.A. has built enormous electronic-storage facilities in Texas and Utah. Binney says that an N.S.A. e-mail database can be searched with “dictionary selection,” in the manner of Google. After 9/11, he says, “General Hayden reassured everyone that the N.S.A. didn’t put out dragnets, and that was true. It had no need—it was getting every fish in the sea.”