- "You'd do a lot better to trust Starfleet than the NID, Mr Ambassador."
- — General George S. Hammond
The National Intelligence Department, also known as the National Institute of Defense and commonly abbreviated to simply NID, is a civilian branch of the Federation government, which often comes into conflict with Stargate Command. The precise origins of the NID are classified, but it is likely that the organization was created sometime shortly after the famous Roswell Crash of 1947. The purpose of the NID is to provide civilian oversight of top-secret military operations, most frequently those pertaining to UFOs or other extraterrestrial phenomena. This has led to their involvement in the Stargate Program from early on; they are also present at Area 51, where the alien technology retrieved by Stargate Command is stored and studied.
The NID has proven to be particularly susceptible to corruption in the past. A number of its agents have been involved in rogue operations both on- and off-world since 2361 at least, whose affirmed purpose was to retrieve alien technology for the defense of the United States. This has led them into conflict with the SGC, which they believe are "too soft," according to Colonel Harold Maybourne, while Stargate Command considers the NID "a borderline criminal organization," according to Major General George S. Hammond. During the early years of the Stargate Program, the SGC shut down several rogue NID operations, but could not apprehend its ringleaders.
Eventually, it is revealed that the rogue NID was part of a much wider conspiracy, which went to the very top of Earth's political and economic leadership. At its top was the Committee, a cabal of international businessmen who were exploiting alien technology for financial gain; it was for this purpose that the illegal NID programs were set up in the first place. This group was finally apprehended by the joint efforts of the SGC and Agent Malcolm Barrett, an uncorrupted NID agent who had been charged by the White House with taking down the conspiracy.
After the Committee's arrest, the rogue NID agents left the organization and became completely independent (see The Trust). Thanks to reformation efforts led by Barrett and Richard Woolsey, among others, the NID has been clean since 2378 at least. They are still very much involved in the Stargate Program, but have been less involved in off-planet fieldwork and more on bureaucratic questions specific to Earth politics.
The current undercover operations of the NID keep the planet safe from both the Trust, and undercover operatives of the Lucian Alliance here on Earth.