Phil Mendelson will be sworn in as the eighth chairman of the D.C. Council on Thursday. (Bill O'Leary/The Washington Post)

Phil Mendelson will be sworn in as the eighth chairman of the D.C. Council on Thursday, a move expected to bring some stability to the body while also setting up yet another citywide special election for a vacant council seat.

Mendelson, 60, will take the oath in a small ceremony in the council chamber after the D.C Board of Elections certifies the results of the Nov. 6 general election.

Mendelson (D) has served as acting chairman since June, when Kwame R. Brown (D) resigned the position. Brown pleaded guilty to bank fraud and campaign finance violations. Mendelson ran in the November special election to fill Brown’s seat, winning 71 percent of the vote against a little-known challenger.

Mendelson has served on the council since 1999 as an at-large member, and his elevation to chairman is expected to result in a relatively smooth transition.

But the council is still reeling from the resignations of Brown and Harry Thomas Jr. (D), the former Ward 5 member who is serving a 38-month prison term for stealing $350,000 from the city. The resignations have left the 13-member council with least one vacancy for all but a month since January.

“The swearing-in is an official step in a process that has already been obvious,” Mendelson said. “But . . . with the swearing-in, there is a clear demarcation from the troubles that have been plaguing the council and the beginning of reform.”

Yet the District must get through another election before the council returns to full strength, because Mendelson will give up his at-large seat when he’s sworn in as chairman.

The special election, likely to be held around April, is expected to put several politicians and activists back on the campaign trail.

Possible candidates

Possible candidates include Sekou Biddle (D), who has served on the school board and the D.C. Council; school board member Patrick Mara, who is a former Republican council candidate; former Prince George’s County Council member Peter Shapiro (D); and A.J. Cooper, who ran unsuccessfully as an independent candidate for the council this year.

Council member Michael A. Brown (I-At Large), who lost his bid for reelection in November after struggling with questions about his finances, is considering running in the special election. Nick T. McCoy, a local Democratic and gay rights activist who most recently worked for President Obama’s campaign in Virginia, is also expected to enter the race.

Before the special election, the 82-member D.C. Democratic State Committee will appoint a temporary replacement for Mendelson.

The appointment, to be decided Dec. 10, is already causing controversy because the leading contender to fill the seat is Anita Bonds, the longtime chairwoman of the Democratic State Committee.

Bonds’s history in city politics dates back to Marion Barry’s first run for school board in 1971. She also worked for former mayors Sharon Pratt and Anthony A. Williams. She is an executive at Fort Myer Construction, a major city contractor.

Bonds was not available to comment, but in past interviews with The Washington Post, she said she wants to join the council to focus on jobs and education.

At least two other candidates — Douglass Sloan and John Capozzi — are seeking the appointment. In separate interviews, they expressed concerns about the process for filling the vacancy.

“Anita does have a clear advantage to get the appointment, but I don’t know if necessarily she is the strongest candidate,” said Sloan, who unsuccessfully challenged Del. Eleanor Holmes Norton (D.C.) in the 2010 Democratic primary for the nonvoting seat in Congress.

Capozzi questioned the state committee’s plans to make the decision so soon.

“They are making it more difficult for the average person to have input,” said Capozzi, who served as the District’s shadow representative to Congress from 1995 to 1997.

No front-runner

Although the interim appointee also secures the backing of the local Democratic Party and some of the advantages of incumbency, there is not expected to be a clear front-runner in the special election, which will probably be a low-turnout contest.

Last year, the state committee selected Biddle as an interim council member after Kwame Brown gave up an at-large seat to become council chairman. Four months later, Vincent B. Orange (D) defeated Biddle in the special election.

Biddle challenged Orange in the Democratic primary this year and lost by fewer than 2,000 votes. In an interview, Biddle said he’s now “very interested” in entering his third council race in less than two years.

“I am just dedicated to making sure D.C. gets the best leadership to bring us together and take us forward,” said Biddle, a vice president of advocacy for UNCF, formerly known as the United Negro College Fund.

Michael A. Brown, who was unseated by independent David Grosso in November, is also sending signals that he, perhaps, hopes his absence from the council will be short-lived.

In an interview with the Afro-American newspaper last week, Brown attributed his loss to unfair media coverage of his financial and campaign troubles and to voter confusion because shadow senator Michael D. Brown was also running in November as an at-large council candidate.

When asked if he planned to run, Brown responded: “You will hear that when I have a chance to talk about it later.”

Shapiro, who unsuccessfully challenged Orange this year, said he is considering the race. “It’s a special election, so we can expect low turnout,” Shapiro said. “So it’s going to come down to the real basics of any campaign: good organizing, fundraising . . . and a very scientific approach to campaigning.”

The likelihood of a small turnout could lure Mara into trying to win a seat on the council for the GOP. Republicans make up less than 7 percent of registered voters in the District, but Mara also has some support among independents and Democrats.

In the 2011 special election, Mara finished second behind Orange, losing by about 1,700 votes.

Mara, who also ran unsuccessfully for the council in 2008, said in an interview that “there is a good possibility” he will run in the special election.

Mike DeBonis contributed to this report.