Much has been made over the last week as WikiLeaks has been releasing portions of what is believed to be a cache of over 250,000 State Department cables believed to have been given to them by Pfc. Bradley Manning.
However, below is evidence that at least one of the cables was previously released by State Department itself creating the possibly other cables were also be declassified by the State Department through mechanism like FOIA and the Mandatory Declassification Review Process.
The cable in question is 75TEHRAN2069 Click the link to access the WikiLeaks' version of it. Below is the electronic copy of it released to the National Archives by the State Department and available through the National Archives' NARA's Access to Archival Databases (AAD). Except for formating and the decision by WikiLeaks (I presume) to call the cable 75TEHRAN2069 instead of 74TEHRAN02069, the cable content is exact. (Of course the dropped "0" could mean that WikiLeaks or Manning altered the documents, but I doub this.)
As the cables are released, it would be fruitful to compare them to cables in the State Department's Electronic Reading Room and the National Archives to see how many have been previously released. Scholars should also consult their personal archives and post any relevant cables that they have had given to them by the State Department