According to last week's indictment of Scooter Libby, a person identified as "Official A" held conversations with reporters about Plame's identity as an undercover CIA operative, information that was classified. News accounts subsequently confirmed that that official was Rove. Under Executive Order 12958, signed by President Clinton in 1995, such a disclosure is grounds for, at a minimum, losing access to classified information.

http://www.truthout.org/docs_2005/110305Y.shtml