Incumbent Robert B. Washington Jr. headed off a strong challenge to win reelection as chairman of the D.C. Democratic State Committee last night after a campaign marked by demands from some members that the committee take a more activist role in the future.

Washington, who has been committee president for the last four years, defeated Washington Teachers Union president William H. Simons by a 32-to-19 vote. The main election issue was Washington's record as chairman, and last-minute politicking appeared to be the deciding factor.

Some members had complained that the committee had been dormant under Washington's stewardship. He has also been criticized for his role in putting together a slate of candidates for the committee in the May 6 election that was endorsed by the city's chief elected officials, a process the members felt was closed to the public.

The state committee sets policy for the local Democratic Party, sometimes chooses who will fill interim seats on the City Council and is sometimes consulted on federal appointments that concern the District.

A group of 22 members of the 55-member committee met recently and agreed to urge both candidates to involve the committee more in government affairs -- including giving testimony before the City Council or Congress on issues such as the city budget. They also suggested that the committee might formally endorse candidates in Democratic primary elections.

While Washington never formally agreed to the demands, disgruntled members apparently were satisfied enough with his responses that many said they voted for him.

The committee was not, however, able to agree on a vice chairman. Some members, most of them supporters of Simons, withheld their votes from the two nominated candidates -- incumbent vice chairman Barbara Bell Clark and Marilyn T. Brown -- preventing either from winning the needed 28-vote majority.

A write-in vote developed for Lorraine Whitlock, a veteran Ward 7 political worker and a Simons supporter, but the committe became bogged down in procedures and recessed until next Thursday, when members will choose a vice chairman, a secretary and treasurer.