In the early 1970s Bussard became Assistant Director under Director Robert Hirsch at the Controlled Thermonuclear Reaction Division of what was then known as the Atomic Energy Commission. They founded the mainline fusion program for the United States: the Tokamak. In June 1995, Bussard claimed in a letter to all fusion laboratories, as well as to key members of the US Congress, that he and the other founders of the program supported the Tokamak not out of conviction that it was the best technical approach but rather as a vehicle for generating political support, thereby allowing them to pursue "all the hopeful new things the mainline labs would not try".
In a 1998 Analog magazine article, fellow fusion researcher Tom Ligon described an easily  built demonstration fusor system along with some of Bussard's ideas for fusion reactors and incredibly powerful spacecraft propulsion systems, with which spacecraft could swiftly move throughout the solar system.