D.C. Council Chairman Linda W. Cropp yesterday entered the 2006 race for mayor, vowing to use her long experience and skills as a consensus builder to fix public schools, make streets safer and ensure that even the poorest residents share in the city's economic revival.

Addressing almost 200 enthusiastic supporters under a brilliant blue sky on historic and newly vibrant U Street NW, Cropp (D) said she would fight to bring fairness and accountability to District government, just as she said she fought last year to revise Mayor Anthony A. Williams's agreement to pay for a new Major League Baseball stadium.

"Many people told me that I shouldn't take on the baseball league. But I did," Cropp said to applause. "I fought for a better agreement and saved taxpayers millions of dollars. That's the kind of hands-on leadership that I bring."

Cropp, a 25-year veteran of city politics who also has served as school board president, is the fourth candidate to enter the campaign and, in some respects, the most formidable. Of the four declared contenders, Cropp alone has won a citywide election. Yesterday, she was flanked by an array of veteran activists and prominent figures in the city's political establishment, including her husband, Dwight, a former aide for then-Mayor Marion Barry; former city administrator Elijah B. Rogers; and other powerbrokers from Barry's administration.

Williams (D) has yet to say whether he will seek a third term. He has said he will announce his plans this fall. Mayoral spokesman Vince Morris said the mayor is unlikely to declare his political intentions before leaving tonight on a scheduled trip to Greece.

Still, at Cropp's rally, the mayor was little more than an afterthought. Instead, her supporters were focused on the man they perceive to be her most serious rival: council member Adrian M. Fenty (D-Ward 4).

"This race is going to boil down to two people: Linda Cropp and Adrian Fenty," said Regina James, a Ward 5 advisory neighborhood commissioner who said the other declared candidates are not serious contenders. Council member Vincent B. Orange Sr. (D-Ward 5) and former telecommunications executive Marie C. Johns have announced their candidacies, and lobbyist Michael A. Brown plans to announce his next week.

"People are looking for a person that has a compassionate understanding of the people of the District of Columbia. Because we're facing some serious issues," said James, who said she's supporting Cropp because the council chairman has proven herself to be "a bridge builder. Instead of taking all these adversarial positions, she says, 'Let's create a solution.' That has been her whole public life.' "

The gravitational pull of Cropp's candidacy was immediately evident. At least two people in the crowd had jumped ship from other campaigns. Marshall Brown, who last year led his son Kwame to victory as an at-large council member, was until recently Johns's chief political adviser. Yesterday, Brown said he will work for Cropp.

Ward 3 resident Ron Bitondo had been a prominent supporter of Fenty's exploratory campaign.

"I like Fenty. He's a terrific person. I've known him a long time," Bitondo said yesterday. "Cropp has proven experience and character. What else can I say?"

Johns played down Brown's defection. Fenty declined to comment on Bitondo.

Of Cropp's candidacy, Fenty said, "I'm going to take all of my opponents seriously."

At 57, Cropp is 23 years older than Fenty, who announced his candidacy in June and has spent the past three months building a citywide political organization. A District native, Fenty has attracted youthful supporters who admire his reputation as a responsive and energetic ward politician.

Cropp, a native of Atlanta, has spent her adult life in Washington. She worked as a teacher and school guidance counselor, then won election to the city school board in 1980, rising to president in 1988. She moved to the District council in 1990 and was elected chairman in a special election in 1997, after the death of former chairman David A. Clarke. Her supporters admire her long experience in city government and her steady leadership of the council, saying she has been a good partner to Williams in engineering the city's economic renaissance.

Yesterday, Cropp led a parade of supporters down U Street NW, greeting shopkeepers and restaurateurs along the way. She opened her address by reflecting on the "struggling African Americans" who put their money in one of the city's first black-owned banks a few blocks away in 1935.

"Just as those early depositors in Industrial Bank had faith in their ability to shape the future, I have faith in our ability to shape the future of this city," Cropp said. "As your mayor, I will respond to your desire, hope and expectation to create a better D.C."

Linda W. Cropp speaks to supporters at the African American Civil War memorial. She is the fourth candidate to announce a bid for D.C. mayor.

Linda W. Cropp walks with supporters along U Street NW to announce her bid for mayor. Cropp, a native of Atlanta, has spent her adult life in Washington.