Reps. Henry Hyde and Daniel Lungren apparently believe that "Tightening Up the Hill's Loose Lips" {op-ed, June 2} will reduce the number of sensitive national security secrets that find their way into the press. The "tightening" they have in mind is the elimination of Congress' two intelligence committees in favor of a single Senate-House joint committee.

They base their argument on the claim that "publicity-seeking members and their free-wheeling staff" cannot keep vital national security secrets to themselves and, therefore, the fewer representatives who know these secrets, the better. But this claim is not borne out by the facts.

In a recent congressional study of newspaper articles divulging classified information to the press, the legislative branch was found to be responsible for only 8 percent of these "leaks." And guess who accounted for the other 92 percent? Let's just say that Reps. Hyde and Lungren are guilty of understatement when they call the executive branch the "masters of the leak." The real solution to this problem lies in a reduction of the number of executive -- not legislative -- personnel who have access to this kind of information.

Congress' two intelligence committees, which Reps. Hyde and Lungren would abolish, provide important "checks and balances" in the intelligence oversight process, and they should be retained. The two-committee system is especially important when one House of Congress is in Republican hands and the other is in Democratic hands, as was the case until just last year.

Each congressional committee is very much the creature of the member of Congress who happens to be its chairman, and the intelligence committees are no exception. If the chairman acts aggressively to ensure sufficient oversight, the committee is likely to live up to its responsibilities. If, on the other hand, his party affiliation or his position on a particular issue (e.g., aid to the contras) tempts him to steer the committee's investigations away from activities that might embarrass his party or threaten the policy he supports, then the oversight process will suffer. Having two competing committees, with two different chairmen, provides a built-in check against such politically motivated obstruction and neglect.

Reps. Hyde and Lungren would like us to "get down to the real business of oversight," but if this is our goal, abolishing the present two-committee oversight process is a step in the wrong direction. ANTHONY C. BEILENSON U.S. Representative (D-Calif.) Chairman Oversight and Evaluation Subcommittee House Select Committee on Intelligence Washington