Although its members are elected on a partisan basis, the D.C. City Council has turned down a proposal to copy Congress and assign its Committee chairmanships only to members of the majority Democratic Party.

If the decision had gone the other way, it could have led to the unseating of Jerry A. Moore Jr. (R-at large) as head of the council's important committee on transport and environment affairs. And it would have disqualified Hilda H. Mason (Statehood at large) from the right to preside over a committee in the future.

As in Congress and state legislatures, the Council Committees screen and draft legislation, often setting major policy directions for the city government. Their chairmen have the right to hire key committee staff members.

On the council, Moore and Mason occupy the two seats that are reserved by the city charter for members of minority parties. The other 11 seats, including that of D.C. Council Chairman Sterling Tucker, are filled by Democrats, reflecting the city's overwhelmingly Democratic voter registration.

During the recent devate on the chairmanship question. Moore fought against partisan appointments, insisting that they would overlook the competency of minority-party members to fill policymaking posts and would create "a rule of absolute dominance" by the Democrats.

Council member Nadine Winter (D-Ward 6) sided with Moore, saying partisan chairmanships would politicize decisions on issues that should be considered on their own meris.

Tucker said the issue was not one for the council to decide in a legislative session.

"This is essentially a party matter," Tucker said. "If the Democratic Party . . . or a caucus (of Democrats on the council . . . takes a position of this kind, we will be guided by (it)."

At present, every council member except Tucker, Dougles E. Moore (D-at large) and newly elected Mason, has a chairmanship.

The decision to keep appointments nonpartisan was made by consensus rather than a formal vote.

Council member David A. Clarke (D-one), who had introduced a measure proposing partisan chairmanships, withdrew it, explaining that "the purpose of my (proposal) has been served" by the debate on it. Clarke heads the council's judiciary committee.

Clarke made his proposal at a time when the council was preparing to fill, on a permanent basis, the chairmanship of its committee on education, recreation and youth affairs. Two council members wanted the job: Mason and William R. Spaulding (D-Ward 5).

Spaulding had been acting chairman since the death early this year of the previous education, recreation and youth affairs committee chairman, Julius Hobson Sr. (Statehood at large). Mason, a professional educator and former member of the D.C. Board of Education, was elected to fill Hobson's coucil seat and was appointed to the education committee.

If Clarke's proposal had carried, it would have barred Mason and assured Spaulding the assingment. As things turned out, Spaulding got the job by a vote of 8 to 4, with council members Marison Barry Jr. (D-at large), Clarke, Jerry Moore and Wilhelmina Rolark (D-Ward 8) casting the negarive votes. Mason abstained.

Council members had intended to assing Mason the chairmanship of the council's special committee on administration and personnel as a consolation prize. That committee also is headed by Spaulding.

Among other things, the special committee is overseeing the impending move of council members' offices from one crampaed wing of the fifth fllor of the District Building to more spacious quarters occupying the building's entire second floor.

Mason turned the job down, explaining that she did not want as a Statehood Party member to referee disputes among Democrats over who should get what perquisites of office.

Tucker said Spaulding would hold both chairmanships, at least temporarily, while a possible shift of the special committee chairmanships is considered.