MORE THAN MOST television viewers realize, the greening and screening of what they see is controlled by the three big networks: ABC, CBS and NBC. The networks' dominance of commercial access automatically makes them gatekeepers of content. It is these networks to which producers come to sell programs, usually at a loss, but always with a hope and incentive of recovery and profit once the networks let the shows go into rerun sales and distribution to various stations. Yet were it not for some important protections adopted by the Federal Communications Commission in 1970, the networks would have an even tighter lock on this market. So guess which three organizations are now pressing for repeal of those protections?

The big three networks are attacking rules that prohibit them from syndicating any programs, or from sharing in the syndication revenues from programs they do not produce. If the networks were to have their way with the FCC, viewers could say goodbye to what little competition has managed to grow in the independent production, distribution and broadcasting of programs; farewell, too, to any growth and program diversity of independent television stations whose lifeblood (and liveliness of fare) is their access to syndicated shows.

In most industries, "deregulation" is supposed to open a market and allow competition to flourish. But it is the other way around here; in commercial TV-- unlike radio, where some 10,000 stations of all financial and organizational sizes can peel off shares of their program markets with modest investments-- these very rules were enacted to increase competition. Repeal would kill competition, not increase it. 2 An example: those "M*A*S*H" reruns on local stations first ran in prime time on CBS, which made its money by selling advertising. Were there no rule prohibiting CBS from start-to-finish ownership of this program, the network could have controlled all rerun sales. Would it have sold "M*A*S*H" reruns to nonaffiliated stations for broadcast during those years or evenings in which it was showing the first- runs? With the rules in effect, the producer--20th Century-Fox Television--was free to sell the reruns to any stations.

The big networks argue that competition is growing through cable, satellite-dish and other innovations in broadcasting, and that they need protection. When they're not talking repeal, though, these same networks are assuring advertisers, stockholders and viewers that they will continue to dominate the news and entertainment market on TV. Either way, these networks already have financial interests in this new technology, and are not exactly punching up "signoff" for the last time.

If the day comes when all those extra new independent channels are beaming quality programs to option-hungry viewers in a majority of America's homes --and if the networks aren't in this business in enough other ways to keep turning hefty profits-- then the FCC might take another look at repeal of the financial interest and syndication rules. But until then, the public's interest in more open competition and program diversity lies in defending these rules against the high-powered attacks of the big three networks. And that defense looks to the votes of reflective FCC members to reject repeal proposals that would strip away these important protections.