2010: Shamai Leibowitz
In May, Mr. Leibowitz, a former FBI contract linguist, pleaded guilty to charges of leaking FBI surveillance transcripts to a blogger. He was sentenced to as many as 20 months in prison, according to The Washington Post.
2010: Stephen Kim
In August, Mr. Kim, a nuclear-proliferation expert on contract with the State Department, pleaded not guilty to charges of leaking information about North Korea to Fox News. The case has not gone to trial.
2010: Jeffrey Sterling
In December, Mr. Sterling, a former CIA agent, pleaded not guilty to charges of disclosing US covert activities to undermine Iran's nuclear weapons program. The case is stalled pending resolution of whether James Risen, a New York Times reporter, will have to testify at trial.
2011: Thomas Drake
Mr. Drake, a former senior executive at the National Security Agency, was charged in 2010 with leaking classified information to a Baltimore Sun reporter about an NSA surveillance program. Prosecutors dropped all charges in June 2011, and Drake pleaded guilty to one unrelated misdemeanor charge of exceeding authorized use of a computer.
2012: John Kiriakou
The former CIA officer was charged in January with five counts of revealing classified information, including waterboarding practices and names of intelligence officers involved in US interrogation of terrorism suspects, to The New York Times and two other unnamed outlets. He pleaded guilty in October to one count of passing classified information to the media. Three months later Mr. Kiriakou was sentenced to 30 months in prison.
2013: Edward Snowden
In June, the former NSA contractor was charged with leaking 'top secret' files on agency surveillance programs that he claims are illegal, giving them to The Washington Post and Britain's Guardian newspaper. He is now a fugitive granted temporary asylum in Russia.
2013: Bradley Manning
Arrested in May 2010, the US Army private is charged with 'aiding the enemy' and six counts of espionage for giving hundreds of thousands of classified military and diplomatic files to WikiLeaks, intending for them to be published on the Internet. A military judge in July 2013 convicted him of the espionage charges but not of aiding the enemy. He was sentenced Aug. 21 to 35 years in prison.