Beltway Law and Legal Definition
The phrase “Beltway” is a form of metonymy. It is an American term for the orbital highway or ring-road that often surrounds major cities. In political reporting the term generally refers to congressional business undertaken inside the highway surrounding. i.e. Washington DC Interstate 495. For example, "a beltway issue" refers to a political issue or debate considered to be of importance only to the political class and of little interest to the general public.
Alternatively, those considered to have a "beltway mentality" are seen as being out of touch with the ordinary voters elsewhere in the country.