By Reem Makhoul, Channon Hodge and Alyssa Kim  The N.S.A.âs Evolution: The National Security Agency was founded in 1952, and its surveillance capabilities were limited by legislation in 1978. But with the attacks of September 2001 came a new sense of urgency.  When Ban Ki-moon, the United Nations secretary general, sat down with President Obama at the White House in April to discuss Syrian chemical weapons, Israeli-Palestinian peace talks and climate change, it was a cordial, routine exchange.  ALLIES AND SPY TARGETS President Obama with other G-20 leaders in St. Petersburg, Russia, in early September, standing between President Dilma Rousseff of Brazil, left, and Chancellor Angela Merkel of Germany.  The National Security Agency nonetheless went to work in advance and intercepted Mr. Banâs talking points for the meeting, a feat the agency later reported as an âoperational highlightâ in a weekly internal brag sheet. It is hard to imagine what edge this could have given Mr. Obama in a friendly chat, if he even saw the N.S.A.âs modest scoop. (The White House wonât say.)  But it was emblematic of an agency that for decades has operated on the principle that any eavesdropping that can be done on a foreign target of any conceivable interest â now or in the future â should be done. After all, American intelligence officials reasoned, whoâs going to find out?  From thousands of classified documents, the National Security Agency emerges as an electronic omnivore of staggering capabilities, eavesdropping and hacking its way around the world to strip governments and other targets of their secrets, all the while enforcing the utmost secrecy about its own operations. It spies routinely on friends as well as foes, as has become obvious in recent weeks; the agencyâs official mission list includes using its surveillance powers to achieve âdiplomatic advantageâ over such allies as France and Germany and âeconomic advantageâ over Japan and Brazil, among other countries.  Mr. Obama found himself in September standing uncomfortably beside the president of Brazil, Dilma Rousseff, who was furious at being named as a target of N.S.A. eavesdropping. Since then, there has been a parade of such protests, from the European Union, Mexico, France, Germany and Spain. Chagrined American officials joke that soon there will be complaints from foreign leaders feeling slighted because the agency had not targeted them.  James R. Clapper Jr., the director of national intelligence, has repeatedly dismissed such objections as brazen hypocrisy from countries that do their own share of spying. But in a recent interview, he acknowledged that the scale of eavesdropping by the N.S.A., with 35,000 workers and $10.8 billion a year, sets it apart. âThereâs no question that from a capability standpoint we probably dwarf everybody on the planet, just about, with perhaps the exception of Russia and China,â he said.  Since Edward J. Snowden began releasing the agencyâs documents in June, the unrelenting stream of disclosures has opened the most extended debate on the agencyâs mission since its creation in 1952. The scrutiny has ignited a crisis of purpose and legitimacy for the N.S.A., the nationâs largest intelligence agency, and the White House has ordered a review of both its domestic and its foreign intelligence collection. While much of the focus has been on whether the agency violates Americansâ privacy, an issue under examination by Congress and two review panels, the anger expressed around the world about American surveillance has prompted far broader questions.  If secrecy can no longer be taken for granted, when does the political risk of eavesdropping overseas outweigh its intelligence benefits? Should foreign citizens, many of whom now rely on American companies for email and Internet services, have any privacy protections from the N.S.A.? Will the American Internet giantsâ collaboration with the agency, voluntary or otherwise, damage them in international markets? And are the agencyâs clandestine efforts to weaken encryption making the Internet less secure for everyone?  Matthew M. Aid, an intelligence historian and author of a 2009 book on the N.S.A., said there is no precedent for the hostile questions coming at the agency from all directions.  âFrom N.S.A.âs point of view, itâs a disaster,â Mr. Aid said. âEvery new disclosure reinforces the notion that the agency needs to be reined in. There are political consequences, and there will be operational consequences.â  A review of classified agency documents obtained by Mr. Snowden and shared with The New York Times by The Guardian, offers a rich sampling of the agencyâs global operations and culture. (At the agencyâs request, The Times is withholding some details that officials said could compromise intelligence operations.) The N.S.A. seems to be listening everywhere in the world, gathering every stray electron that might add, however minutely, to the United States governmentâs knowledge of the world. To some Americans, that may be a comfort. To others, and to people overseas, that may suggest an agency out of control.
The National Security Agency finds itself under intense pressure after disclosures of spying on allies and rivals alike, but it defends the wide net it casts.