The Declassified Documents Reference System (DDRS) is now known as U.S. Declassified Documents and can be accessed here:
U.S. Declassified Documents can also be searched via the Gale Artemis platform
To search the U.S. Declassifed Documents resource only, click on the “Searching 10 of 10 databases” tab, untick the “Check all” tick box and tick just the “U.S. Declassified Documents Online” tick box (bottom right). You can filter search results by document type, classification level, publication year and by other categories. Results can be analysed using the built-in Term Frequency and Term Clusters tools.
U.S. Declassified Documents Online provides immediate access to a broad range of previously classified federal records spanning the twentieth and twenty first centuries. The collection brings together the most sensitive documents from all the presidential libraries and numerous executive agencies in a single, easily searchable database. The search and discovery interface for the collection allows researchers to locate the full text of documents and quickly filter their search results by document type, issue date, source institution, classification level, and date declassified as well as other document characteristics.
The collection is the most comprehensive compilation of declassified documents from the executive branch. The types of materials include intelligence studies, policy papers, diplomatic correspondence, cabinet meeting minutes, briefing materials, and domestic surveillance and military reports. The collection editors have actively monitored the release of formerly classified documents from presidential libraries. They have also added numerous major releases of declassified documents from the Department of State, Department of Defense, Central Intelligence Agency, Federal Bureau of Investigation, Joint Chiefs of Staff, and other executive agencies.
Because the majority of the documents are presidential records and all of them were formerly classified, these records provide a unique, behind-the-scenes view of the highest level of American policymaking on the most sensitive issues of national security and foreign policy. Materials cover virtually every significant foreign policy development and international crisis, from the years leading up to the First World War through the end of the Cold War. Topics include the outbreak and course of the Second World War, the end of colonialism in the global south, the Korean War, the Vietnam War, U.S. relations with non-aligned states in the 1960s, U.S.-Soviet relations in the era of détente, international trade, nuclear proliferation, conflict in the Middle East, and the War on Terrorism. The collection also traces important sources on sensitive episodes within the United States such as domestic surveillance, the civil rights and anti-war movements, abuse of government power, and home-grown terrorism.
The declassification of government documents occurs slowly and unpredictably and USDDO allows researchers to readily find the latest releases. To get the most out of this collection, it is helpful to understand generally how the federal government has handled classified materials. There are three basic levels of classification for national security information: confidential, secret, and top secret. The test for assigning confidential classification is whether its unauthorized disclosure could reasonably be expected to cause damage to the national security. Secret documents are expected to have the potential to cause serious damage. Top secret documents require the highest degree of protection and may cause exceptionally grave damage to national security. Examples of exceptionally grave damage include armed hostilities against the United States or its allies; disruption of foreign relations vitally affecting the national security; the revelation of sensitive intelligence operations; and the disclosure of scientific or technological developments vital to the national security.
When archival collections held by the National Archives and Records Administration, such as the records at the presidential libraries, are opened for research, individual classified documents are removed from these collections. Entire series of federal records are also kept closed for years because they contain a high proportion of classified items. As time passes the federal government determines when restrictions on specific classified documents are no longer warranted, and it publicly releases those records. At times classified documents are partially released with portions redacted. These declassification determinations are made both as a result of the systematic review of classified documents by the agencies that created them, guided by the priorities of the federal government, and in response to public requests for mandatory declassification review. U.S. Declassified Documents Online compiles the declassified documents, released individually or in sets, that fill in the most sensitive gaps of the historical record left by the federal government.