After hours of debate, a majority of the Prince George's County Council agreed last night to support Roy Dabney, a black bank executive and former president of the county Chamber of Commerce, to fill a council vacancy created by the retirement of Francis B. Francois.

Dabney, a 37-year-old Bowie resident and political unknown, must be approved by the council in an open session vote today before he can assume the $24,000-a-year post. His selection was virtually guaranteed last night after nine of the 10 council members agreed at a close dinner meeting at the La Scala Restaurant in Suitland to support him instead of two other candidates.

"Dabney's the winner after 13 rounds," said council member Gerard McDonough, who had been backing John Lally, one of the other two candidates. "Everyone fought a hell of a fight [for their respective candidates]. Everyone walked a mile. Obviously Dabney has a lot of credibility as a candidate or he wouldn't come out of the meeting. Everyone was comfortable supporting him."

The agreement to back Dabney was a significant victory for the county's black leadership -- in particular State Sen. Tommie Broadwater (D) and the two black representatives currently on the all-Democratic council. It indicates how increasingly powerful that growing community, which frequently operates as a cohesive political bloc, has become in county political affairs.

With Dabney on the council, the II-member group will have three black members at a time when the county's minority residents have grown to represent some 30 to 40 percent of the county's population.

Dabney's selection, after 13 rounds of straw votes, capped nearly three months of often intense political activity among county Democrats sparked by Francois' surprise announcement last June that he was leaving county government. Because Francois is a Democrat, the Democratic Party was given the power to select his replacement.

Unlike past years, when the Democrats, through a well-controlled party organization, were able to agree fairly quickly on appointments and the selection of political candidates, the process leading to Dabney's selection was marked by an overwhelming lack of consensus that resulted in many party regulars being overlooked for the prestigious spot on the council.

The process saw a rejuvenated party central committee acting independently of leadership for the first time in years as it selected the three finalists for the job and various factions of the party competing for influence.

In the end, a list of some 20 persons was whittled down to three -- Dabney, former Kelly aide Lally and former Bowie mayor William Wildman. It was over these three that the 10 council members argued last night.

At issue was not just the $24,000 post on the county's legislative body but questions of party power, its future and of philosophy and political style. Dabney managed to win the support of the council, despite lacking party experience, because of black community pressure exerted through Broadwater and taken before the council by member Deborah Marshall.

The Dabney effort was aided by a split on the council that was partly the product of philosophy and partly of style. The more conservative members backed Wildman and several moderates supported Lally. With none of the three able to win the support of six council members, Dabney turned out to be the compromise candidate, who had no political enemies and alienated neither side.