The first revelations are published  Documents leaked by Edward Snowden lead to the exposure of a pair of secret NSA programs. The Guardian discloses that the agency is gathering the telephone records of millions of Americans from Verizon as part of what is later revealed to be an even broader collection effort. A day later, The Washington Post and the Guardian report that the NSA is collecting a wide range of digital information from nine private Internet firms as part of a program known as PRISM.  INTERACTIVE:NSA slides explain the PRISM data-collection program  VIDEO:NSA leak: Source believes consequences inevitable  Snowden reveals himself as the leaker  The former NSA contractor comes forward. He later travels from Hong Kong to Russia, where he was granted one year of asylum.  Audit: NSA broke privacy rules  The Post reveals an internal audit that showed the agency had broken privacy rules or overstepped its legal authority thousands of times each year since Congress granted it broad new powers in 2008. Later, a declassified court opinion revealed that, for almost three years, the NSA searched a massive phone record database in violation of privacy rules.  GRAPHIC:The Foreign Intelligence Surveillance Court  The âblack budgetâ is revealed  The 178-page budget summary for the National Intelligence Program is revealed by The Post; it details the successes, failures and objectives of the 16 spy agencies that make up the U.S. intelligence community. The budget also revealed that the NSA is paying U.S. companies for access to their communications networks.  Brazilâs O Globo newspaper reports that the NSA spied on Brazilian President Dilma Rousseff and top aides. Rousseff later cancels a state visit to Washington and denounced electronic espionage by the NSA in an address before the United Nations.  Court decision upholding NSA phone program declassified  The gathering of âall call detail recordsâ for counterterrorism purposes is justified, according to a declassified decision from the secretive Foreign Intelligence Surveillance Court. The courtâs chief judge, U.S. District Judge Reggie B. Walton, conceded to The Post that judges must depend on the government to report when it acts improperly.  Germans launch probe of spying allegations  The Post reveals that the NSA is harvesting hundreds of millions of contact lists from personal e-mail and instant messaging accounts, many belonging to Americans.  NSAâs surveillance of world leaders disclosed  After Der Spiegel reports that German Chancellor Angela Merkelâs cellphone may have been tapped, the Guardian reports that the agency monitored the calls of scores of world leaders. European officials threaten to delay trade negotiations and Germans launch an investigation. The revelations also anger key U.S. lawmakers, including Sen. Dianne Feinstein (D-Calif.), head of the Senate Intelligence Committee.  GRAPHIC:How the NSA is infiltrating private networks  NSA taps links to Yahoo, Google data center  By infiltrating the tech giantsâ networks, the agency is collecting at will from hundreds of millions of user accounts, many belonging to Americans, The Post reports. Several companies later embark on initiatives to strengthen data encryption in hopes of thwarting government spying.  NSAâs collection of cellphone location records revealed  The agency is gathering nearly 5 billion records a day on the whereabouts of cellphones around the world, and while it doesnât target Americansâ location data, it acquires a substantial amount of data about their whereabouts âincidentally.â  GRAPHIC:How the NSA is tracking people right now  VIDEO:How the NSA uses cellphone tracking to find targets  Tech companies call for new limits on surveillance  The big firmsâ requests that the government allow them to be more transparent morph into a call for strict new curbs on surveillance that could reshape intelligence operations. The companies express concern over the future of their businesses, which rely at least in part on user trust.  Judge rules collection of Americansâ phone records almost certainly illegal  In his ruling, Richard J. Leon, a judge on the U.S. District Court for the District of Columbia, says he cannot imagine âa more âindiscriminateâ and âarbitrary invasionâ than this systematic and high tech collection and retention of personal data on virtually every single citizen for purposes of querying and analyzing it without prior judicial approval.â  Review panel urges new curbs on surveillance  The group, appointed by President Obama in August in response to revelations about NSA programs, makes a host of recommendations, including that the agency should end the collection of virtually all Americansâ phone records. The administration says it will announce in January how it will respond to the recommendations, amid indications it will end the bulk collection of phone records.
The National Security Agency has been forced to respond to unprecedented disclosures about its surveillance programs. Those programs have been assailed as a violation of privacy rights by critics and defended as critical to U.S. national security by intelligence officials. Explore the revelations and the fallout.