Four candidates in a contentious Brooklyn congressional race addressed their chief political weaknesses in a televised debate last night. One hopeful admitted not graduating from college, while another answered charges that he was an opportunist taking advantage of a divided field in a predominantly black district.

The tense face-off largely pitted David Yassky, the lone white candidate running in Brooklyn’s 11th district, against rivals Yvette Clarke, Chris Owens, and Carl Andrews. On display were the racial tensions that have drawn attention to the campaign from across the city.

A City Council member representing a district that lies mostly outside the 11th district’s boundaries, Mr. Yassky moved into the area only recently.

“There’s no doubt that David could have moved into any congressional district and run,” Ms. Clarke said of her colleague in the council. “He chose this district.”

Mr. Yassky, a former aide to then-Rep. Charles Schumer, countered that he had moved just three blocks into the district and that the issue mattered more to the press than to the voters, who he said “want someone who’s going to get results in Washington.”

The other three candidates cited their lifelong residency in the district, which comprises Crown Heights, Brownsville, and parts of Park Slope.

The exchanges came at the outset of a debate that focused more on the candidates’ liabilities than on their strengths or ideas. For Ms. Clarke, that meant repeating the embarrassing admission that she never graduated from college. For Mr. Andrews, a state senator, it was dealing with questions regarding his close association with a former Brooklyn Democratic leader, Clarence Norman, who was convicted of corruption charges. And for Mr. Owens, son of the retiring incumbent, Major Owens, the challenge was asserting his qualifications for Congress as the only candidate never to hold elected office.

Ms. Clarke said it was a mistake to sign a city voter form stating that she received a bachelor’s degree from Oberlin College despite not fulfilling the requirements for graduation. “I’m really embarrassed by it,” she said. “I’m really embarrassed by it.”

Of the three other candidates, only Mr. Owens strongly criticized Ms. Clarke, saying the error pointed to “messiness and incompetence.”

Mr. Andrews struggled to distance himself from Norman and appeared uncomfortable discussing the disgraced ex-assemblyman. “Clarence Norman? What about Clarence Norman? My name is Carl Andrews,” he said when pressed on his ties to Norman.

Asked to evaluate Norman as the county leader, Mr. Andrews said, “He did some good things as a county leader, and he did some bad things as a county leader.”

While declining to attack Mr. Andrews, Ms. Clarke and Mr. Owens took the opportunity to assert their independence from the party establishment and champion their efforts as reformers. “I’ve never enjoyed county support under Clarence Norman,” Ms. Clarke said, seeming to boast. Mr. Owens cited his leadership of a reform coalition in the 1990s.

The debate, televised on New York 1, turned personal at times. Ms. Clarke criticized Mr. Yassky for taking too much credit for achievements in the City Council at the expense of his colleagues. And earlier, when Ms. Clarke tried to assert her support among women, Mr. Owens retorted, “I guess that explains why the National Organization of Women endorsed me.”

The candidates spent relatively little time discussing what they would actually do if elected, but all attacked the Iraq war, the Republican-led Congress, and the Bush administration. Asked to cite the three most pressing issues in the district, all the candidates listed affordable housing, while only Mr. Yassky did not name immigration.

Of the four candidates, only Ms. Clarke endorsed the controversial Atlantic Yards project as it currently