"Inside the Beltway" is an American idiom used to characterize matters of greater interest to U.S. federal government officials, contractors, lobbyists, and media personnel, than to their general public.
Some speakers of American English now use "beltway" as a metonym for federal government insiders (cf.
[1] Multiple political columns are titled after the phrase, including the Washington Times,[2] American University's magazine,[3] and columnist John McCaslin.
Reporting in 1975 on the prospect of a reexamination of the Warren Commission's findings concerning the assassination of John F. Kennedy, newspaper journalist Nicholas M. Horrock wrote: In the White House of Richard M. Nixon, it was said that Watergate would become serious only if it 'got outside the Washington Beltway', if the depths of the disgrace were understood by the American people.
It can be said that the myriad doubts about the Warren Commission's findings in the death of President Kennedy represent a reverse situation.