Criminal Prohibitions on Leaks and Other Disclosures of Classified Defense Information [Updated March 7, 2017] [open pdf - 1MB]
From the Summary: "Recent unauthorized disclosures of information concerning activities in the White House, and the publication of large quantities of classified information by WikiLeaks and other organizations and news outlets, have prompted congressional interest in criminal prohibitions on disclosure of classified information. While some have described recent leaks of classified information as 'illegal' and 'criminal,' there is no single statute that criminalizes any unauthorized disclosure of classified information. Instead, the legal framework is based on a complex and often overlapping set of statutes with provisions that differ depending on, among other factors, what information was disclosed, to whom it was given, and the intentions of the discloser. This report identifies statutory prohibitions that may be implicated by the unauthorized release of classified information, and it examines the elements necessary to secure a conviction under the Espionage Act and applicable statutes."
CRS Report for Congress, R41404
Congressional Research Service: https://crsreports.congress.gov/