Even before the establishment of the SGC, the stargate has been closely tied to the Pentagon. The top secret research notes and files of the US Army Air Corps regarding the early stargate experiments in 1945 were stored at the Pentagon until they were declassified and sent to the newly formed SGC in 1997. Before being assigned to the SGC, Samantha Carter had spent two years in Washington at the Pentagon working to develop a stargate program, and her work there had also included research into nano-technology and genetics, with Dr. Timothy Harlow.
As a military operation under the Joint Chiefs of Staff, the SGC was established under the jurisdiction of the Pentagon. The commander of the SGC closely coordinates with the Pentagon both for routine missions and extraordinary situations, and representatives from the Pentagon frequently visit the facility in the role of liaison. When Teal'c first came to Earth from Chulak, Colonel Kennedy arrived from the Pentagon to interrogate him for US Military Intelligence. Colonel Kennedy was later replaced by Colonel Maybourne of the NID. Major Samuels of the SGC was promoted and transferred to the Pentagon where he was assigned to Stargate Mission Analysis. Major Davis, from the Office of the Joint Chiefs, has frequently cooperated with the SGC in the role of liaison to the Pentagon. General Vidrine of the Pentagon coordinated with the SGC during the test flights of the X-301, and he was later assigned by the Pentagon to oversee BC-303 production. Dr. McKay, seen by the Pentagon as one of the stargate's foremost experts, reported directly to the Chief of Staff and had been assigned by the Pentagon to serve at Area 51, the SGC, and in Russia. Colonel Simmons of the Pentagon used the mandate of the NID to apply pressure to the SGC in the pursuit of superior technologies, and Richard Woolsey had served with the Pentagon before resigning and taking a position with the NID.
The Pentagon has the power to authorize missions and to oversee facilities related to the Stargate Program including the off-world Alpha and Gamma Sites, the White Rock Research Station in Antarctica, and Area 51. It has cooperated with the Russian government in coordinating the US and Russian stargate programs, and it was the decision of the Pentagon to arrange a briefing in which the Stargate Program was disclosed to representatives of China, France, and the UK.
When General Hammond was transferred from the SGC, he was promoted and accepted the position as the head of Homeworld Security, overseeing all things related to Earth's defense. From his position at the Pentagon, he maintained close communication with his successor at the SGC, General O'Neill. The following year, General O'Neill was also transferred to Washington, and he continued to oversee the Stargate Program through his communications with General Landry.
The SGC has remained a military operation despite the increased influence of the International Oversight Advisory, the civilian organization that was established after the disclosure of the Stargate Program to certain allied nations. The IOA has the ability to control the flow of funding into the SGC, and the Pentagon coordinates closely with the IOA. It was the Pentagon that made arrangements for delegates from the IOA to make their first off-world visit through the stargate for a tour of the Gamma Site in an effort to improve public relations and to reassure the IOA of the job the SGC was doing.
Cross Reference: Ambassador from Britain, Ambassador from China, Ambassador from France, Area 51, Area 52, Samantha Carter, Cheyenne Mountain Complex, Paul Davis, Disclosure, Major Gibson, George Hammond, Timothy Harlow, International Oversight Advisory, Colonel Kennedy, Harry Maybourne, Francis Maynard, Rodney McKay, NID, Jack O'Neill, Russians, Colonel Samuels, SGC, Frank Simmons, Arthur Simms, David Swift, General Vidrine, Richard Woolsey