A heated and procedurally entangled meeting of the D.C. Democratic State Committee adjourned abruptly in confusion last night, following the first sharply defined intraparty clash between supporters of unannounced mayoral candidates Sterling Tucker and Marion Barry.

Earlier in the evening, the committee had voted 19 to 18 to adopt a proposal by chairman Robert B. Washington Jr. to add 12 additional members to the 50-member body.

Washington is viewed by many committee members as a strong supporter of Tucker. Most of those voting against his proposal expressed concern that Washington would have a major role in the selection of the new members, and would use that advantage to bring in more Tucker supporters.

At present, committee members are believed to be near evenly divided between Tucker and Barry. However, with the addition of 12 new members, it was feared there might be enough Tucker supporters on the committee to comprise the two-thirds majority necessary to endorse Tucker for mayor in next year's District election.

As the Barry supporters were seeking a means of getting another vote on the plan in a caucus in the hallway outside the City Council chambers, where the meeting was held, Washington recognized a motion for adjournment from Ron Linton, who had been the major supporter of Washington's proposal.

The surprised opponents of the Washington plan stormed back into the chambers only to find the meeting adjourned with much of its agenda still to be acted on.

"I have never seen anything so ridiculous in my life. It is strickly a political move to determine whether the Democratic state committee will get a two-thirds vote to endorse Sterling Tucker." said committee vice chairman Lillian Adkins Sedgwick, a supporter of Barry. "Clearly, Mr. Washington thought if the vote was taken again he would have lost."

"(That's) sour grapes, it sounds like somebody lost." Washington responded. "People lost. They lost on a fair and square basis."

The State Committee is the elected and recognized Democratic organization in the District. Nearly all its present members were elected in May 1976, when the Unity '76 Coalition, led by Tucker, Barry and D.C. Del. Walter E. Fauntroy, seized overwhelming control of the committee.

During the past several months, as City Council Chairman Tucker and At Large Councilman Barry have tried to put together the first stages of their potential mayoral campaign organizations, members of the previously unified state committee have been forced to choose sides.

Many political observers considered it only a matter of time before the Barry-Tucker split within the state committee surfaced in some way. Last night, with the assistance of a good deal of parliamentary confusion and some other state committee members favorable to neither candidate, those divisions became apparent.

The proposed amendment to the committee's constitution will not automatically give Washington the ability unilaterally to appoint 12 new members. The additional at large members must be approved by the state committee.

Washington and other supporters of his amendment contended that the organization as currently structured does not have adequate representation from many groups that have traditionally been a part of the Democratic Party's base, including Latinos, professional, businessmen, elected city officials and young people. The first point of contention last night came when Washington ruled that only a simply majority of those member present would be necessary to approve the amendment. Opponents contended that a majority of the entire committee - 26 members - would be necessary for approval.

In an atmosphere that some said created confusion of what was being voted on. Washington's opinion was upheld. Later the committee voted 10 to 18, with one abstention, to approve the Washington amendment. Many opponents of the amendment, believing apparently incorrectly, that 19 votes was not sufficient to approve the amendment, applauded.

Moments later, however, when informed that they had actually lost, the foes found one person whom they said was willing to change her vote, and were planning a move for reconsideration, when the meeting was adjourned.