Edward Snowden's claim to have leaked details about the NSA's PRISM program is the latest in a line of people who have leaked sensitive government documents.
1971: The Pentagon Papers When Daniel Ellsberg, a strategic analyst for the RAND Corporation, leaked the Pentagon Papers to the press 42 years ago, he was certain he would "go to prison for life."
The Papers consisted of classified Department of Defense documents revealing the Kennedy and Johnson administrations' early knowledge that a loss was likely in the Vietnam War.
Ellsberg was brought to trial for charges under the Espionage Act, but the charges were dismissed when the judge discovered that Nixon administration officials had tried to break into the office of Ellsberg's psychiatrist to discredit him.
Ellsberg has applauded Snowden's actions.
"In my estimation, there has not been in American history a more important leak than Edward Snowden's release of NSA material –and that definitely includes the Pentagon Papers 40 years ago," Ellsberg wrote in The Guardian yesterday.
1972: Watergate He was best known as "Deep Throat," but W. Mark Felt was also known in official circles as the associate director of the FBI between 1972 and 1973.
During that time, he provided critical information to The Washington Post's Bob Woodward and Carl Bernstein on the Watergate scandal and the Nixon White House's connection to it.
This information led to the resignation of President Richard Nixon on Aug. 9, 1974.
Felt's identity was kept secret until May 31, 2005, when Vanity Fair published the article, "'I'm the Guy They Called Deep Throat.'"
After the revelation, Woodward wrote about Felt's insistence on protecting his identity: "He beat it into my head: secrecy at all cost, no loose talk, no talk about him at all, no indication to anyone that such a secret source existed."
Woodward and Bernstein wrote in their book "All the President's Men" that "Deep Throat was trying to protect the office, to effect a change in its conduct before all was lost."
1986: Iran-Contra Affair Serving as a Shia cleric in Iran, Mehdi Hashemi opposed his country's attempts to obtain weapons from the U.S. and Israel for its war against Iraq.
He leaked news of the purchases to the Lebanese newspaper Ash-Shiraa, which published an article about the secret exchanges on Nov. 3, 1986.
The news created a scandal in America because it was revealed that the U.S. traded the weapons to its enemy Iran in the hopes of freeing U.S. hostages being held by Iran.
Some of the arms' sales were then illegally directed toward helping fund the anti-communist efforts of the Contras in Nicaragua.
Multiple investigations followed the news, but sufficient evidence could not be found that President Reagan knew of the scope of the program.
Eleven officials were convicted for the efforts, but all of their convictions were either reversed on appeal or pardoned by President George H.W. Bush.
As for Hashemi, he was executed by the Islamic Republic in 1987 for murder and sedition. No link between his execution and his role in the scandal could be proved.
|Lewis "Scooter" Libby|
2003: The Valerie Plame Case On July 14, 2003, Robert Novak wrote an editorial for The Washington Post criticizing former U.S. diplomat Joseph Wilson and revealing that his wife, CIA agent Valerie Plame, was an "agency operative."
Wilson had written a New York Times article that called into question the Bush administration's motives for the invasion of Iraq.
After Novak's editorial, Wilson accused the White House of leaking Plame's identity as revenge for his criticism. Special prosecutor Patrick Fitzgerald pursued an investigation into a possible link between the leak and top White House officials, including President Bush and Vice President Cheney.
Fitzgerald concluded that I. Lewis "Scooter" Libby, chief of staff to the vice president, had learned of Plame's identity from Cheney in June 2003 and then passed the information on to journalists in July.
In 2007, Libby was convicted on one count of obstruction of justice, one count of perjury, and two counts of making false statements. He was sentenced to 30 months in prison, which President George W. Bush commuted.
2010: Wikileaks Pfc. Bradley Manning was arrested in May 2010 in Iraq after computer hacker Adrian Lamo informed the FBI that Manning had admitted to passing hundreds of thousands of classified files to the website WikiLeaks.
The leaks first appeared in February 2010 and continued until November. Arguably the most controversial of the files was the "Collateral Murder" video, which showed a Baghdad airstrike by a U.S. helicopter killing several civilians.
Manning was arrested and charged with 22 offenses. He pleaded guilty to 10 of them in February 2013, which could carry a sentence of up to 20 years.
The trial for the remaining 12 charges began on June 3 and could result in a life sentence for Manning.
2011: The Risen Leaks On Jan. 6, 2011, former CIA officer Jeffrey Sterling was arrested for allegedly leaking information about a weapons intelligence program and the identity of a "human asset" to New York Times reporter James Risen.
The Justice Department believes that Sterling released the leaks in 2003 in revenge for unresolved issues with the CIA. Risen then used the information for his 2006 book, "State of War: The Secret History of the CIA and the Bush Administration."