In an attempt to keep classified information on the NSA’s vast and varied spying programs off of unauthorized computers, the US Army is blocking access to the website of UK newspaper The Guardian on its network. Writing to the Monterey Herald, an Army spokesman stated that "some access to press coverage and online content about the NSA leaks" was being filtered as part of routine "network hygiene" done to limit the scope of unauthorized disclosures of classified material.
"Classified information remains classified."
The move is reminiscent of the 2010 decision to block the websites of the New York Times, the Guardian, and other news organizations for hosting secret US diplomatic cables provided by WikiLeaks. At the time, the White House wrote that "classified information, whether or not already posted on public websites or disclosed to the media, remains classified, and must be treated as such by federal employees and contractors, until it is declassified by an appropriate US Government authority."
Blocking access to The Guardian from unclassified Army computers obviously isn’t going to stop the material from getting in the hands of rank and file employees, but it’s essentially all the military can do to stop the spread of information. A representative of NETCOM (part of Cyber Command) wrote that the Department of Defense is "not going to block websites from the American public in general."