IT WASN'T known to all that many people, but during the most tense racial times of the 1960s in this city, President Johnson and Mayor Walter Washington could -- and did -- turn to a small but enormously helpful group of religious leaders for behind-the-scenes advice, assistance and communication between the races. The members of this interreligious committee volunteered out of a shared deep commitment to racial tolerance as well as a remarkably good network of sources from street people to Cabinet members and the president. And one of the most concerned and community-minded associates in this constructive "underground" was Isaac Franck, executive vice president of the Jewish Community Council of Greater Washington, who died Tuesday at the age of 76.

Dr. Franck's better-known accomplishments icluded a successful 25-year stewardship of the Jewish Council that turned this organization into an influential forum. With a steady hand and the instincts of a trusted mediator, he gave the council not only a sense of cohesion but respect as a local institution.

After riots here in 1968 put new strains on relations between blacks and whites generally -- and blacks and Jews in particular -- Dr. Franck merely intensified his efforts to preserve and build the old alliances that had worked so well for the rights of all victims of discrimination. With the ministers of the coalition and his other contacts, he coordinated efforts to collect and dispense food, to find jobs, to secure housing and to lobby wherever necessary to improve police-community relations, to end discrimination in housing and to upgrade public education from kindergarten through college.

Through it all, Dr. Franck sought no personal credit; he was pleased when plans succeeded and challenged when they seemed to be thwarted. With warmth, humor, intelligence and energy, he continued to work for interreligious and interracial understanding after his retirement from the council in 1973. Greater Washington -- and what is good about it today -- is linked in no small way to the contributions of Dr. Franck, and that is why he will be remembered with special affection.