The Guantanamo documents were not published by the media until this past Sunday, but McClatchy and other news organizations say they received them earlier under embargo. So it's not clear whether this subpoena is related to the Gitmo documents. It does seem related to Wikileaks.

More from Glenn:

The Grand Jury is investigating possible violations of the Espionage Act (18 U.S.C. 793), a draconian 1917 law under which no non-government-employee has ever been convicted for disclosing classified information....[The subpoena] also cites the conspiracy statute, 18 U.S.C. 371, as well as the conspiracy provision of the Espionage Act (subsection (g)).....Also cited is 18 U.S.C. 641, which makes it a crime to "embezzle, steal, purloin, or knowingly convert . . any record, voucher, money, or thing of value of the United States."

Glenn quotes the New York Times which reported in December the Government seems to be pursing not just those who leaked the documents, but those who helped the leaker acquire them.