In Washington, D.C., the Korean war comes on at 7:30 p.m., five nights a week - when reruns of the TV series ''M*A*S*H'' are shown on a local station. For those who prefer a different type of humor, ''Three's Company'' airs at 7 o'clock, competing with network news. ''The Jeffersons'' are on twice an evening: at 6 p.m., and again at 6:30.
All across the nation the airwaves are flooded with reruns during late afternoon and early prime time. These aged network hits are not broadcast this often because they are necessarily great art. They are on because they still attract large audiences.
Reruns mean big bucks - and a fierce lobbyists' war now raging in Washington centers on who should get a share of this money. On one side are Hollywood producers, on the other the ''big three'' networks. Both sides say that if the other wins, free TV will become even more of a wasteland than it already is.
Think of the whole thing as a miniseries called ''The Winds of Deregulation.'' At issue are the syndication and financial-interest rules, Federal Communications Commission (FCC) regulations adopted in 1970 that prevent TV networks from investing in shows they don't produce themselves and from owning syndication rights.
NBC, for example, doesn't own ''Hill Street Blues.'' The network rents the right to show each episode twice. MTM Enterprises, the company that actually films the series, retains ownership and at some point will probably syndicate it - rent old episodes to individual stations.
Networks were barred from the $800 million-a-year syndication business because the FCC feared it would give them too much power over program production. But the commission began to take another look at the rules in 1977. This fall, the FCC proposed letting the networks gradually back into syndication , concluding in a special study that the prohibitions were ''misguided at best.''