THE 26-to-7 vote in the House Foreign Affairs Committee to put conditions on military aid to El Salvador is striking evidence of the misgivings felt on both sides of the aisle about administration policy. There is scant appetite evident in Congress to renew the congressional-executive foreign policy battles that flourished in the Vietnam War period. But eight Republicans on the committee, a majority, joined all 18 Democrats voting to demand that, before new aid flows, the president be obliged to certify that the Salvadoran junta is moving ahead on human rights, control of its own security forces, economic reform, openess to negotiations and free elections.

Something important has happened since the Reagan administration set out two months ago to demonstrate that "the communists have intensified and widened" a local insurgency and made El Salvador "a textbook case of indirect armed aggression by communist powers through Cuba. "The administration made that demonstration, to the satisfaction, we surmise, of most legislators. But something else has been demonstrated that the administration paid little attention to two months ago. Some activities of the junta are reprehensible and self-defeating. You don't have to call this a contradiction, just a development, but it has to be dealt with somehow.

The administration's way is the old whisper-in-the-ear approach: pledge fidelity and support and with it gain a hearing and leverage to tip the balance within the junta away from the right wing and toward the moderates. This is not an insubstantial theory, but it carries the familiar risk that the junta's hard-liners will simply pocket the military aid and run. It was to head off this possibility that the House committee voted to tie the aid. The rationale is to give the Salvadoran moderates the extra muscle they need to sway the hard-liners.

We are sympathetic to the purposes of the House committee but dubious about its remedy. It seems to us too early to be writing a law on the premise that the administration, which insists it supports the House's purposes, is acting in bad faith. It may be useful for the administration, in its dealing in El Salvador, to be able to show that a good number of Americans are breathing down its neck and demanding a principled performance. Our sense of things is, however, that while the administration could use some expressions of concern about El Salvador, it doesn't need this hard a shove -- at least, not yet.