Assemblyman Vito Lopez, the Democratic leader of Brooklyn who has presented himself as a reformer since succeeding Clarence Norman Jr., who is serving time for corruption charges, is facing questions about whether he played a role in his daughter’s ascension to a judgeship, as well as the broader political influence he wields over the selection and election of judges.

Political parties in New York State have the authority to choose judicial nominees for Supreme Court seats, giving Mr. Lopez, as the head of the party, great influence, if not total control, over who is picked each year.

This fall, when there are eight vacancies for Supreme Court justices in Brooklyn, Mr. Lopez will face a test, as attention focuses on whether he selects judicial candidates based on merit, rather than their standing in the party hierarchy.

The Supreme Court dismissed earlier this year a long-pending challenge to the party’s influence on judicial elections, ensuring that Mr. Lopez will hold on to his influence. While judges in Brooklyn are elected or appointed, the Democratic Party plays a major role in selecting and nominating candidates.

“The thing with the Brooklyn judiciary is that it is, if not the last, the most lucrative bastion of the old-time political machine,” a political science professor at Baruch College, Douglas Muzzio, said. “It’s also a place where who you know and who you’re related to really counts. It’s the old-time ‘take care of your own and take care of me’ school of governance.” The focus on Mr. Lopez comes after Governor Paterson on Friday renominated Mr. Lopez’s daughter, Gina Lopez Summa, to a judgeship in the Court of Claims, putting her up for a nine-year term.

A report in yesterday’s Daily News highlighted another judge linked to Mr. Lopez, Justice Jack Battaglia, who is the brother of Mr. Lopez’s girlfriend. Mr. Battaglia is planning to sue the city for $1 million after he slipped on a wet floor in the courthouse where he works, according to the report. The president of the Central Brooklyn Independent Democrats, Christopher Owens, said his organization is opposed to the concentration of political power in the hands of any one individual when it comes to selecting judges. “We were concerned when Clarence Norman had that power. We are concerned with Vito Lopez having that power,” he said.

Norman, who preceded Mr. Lopez as the Brooklyn Democratic party leader and was an assemblyman for 23 years, began serving one to three years in jail last summer on charges that he coerced a judicial candidate into spending campaign money on political consultants he had selected. He was already serving terms for other corruption charges.

Mr. Owens, whose father is Rep. Major Owens, said the “reform Democratic community” in Brooklyn is disappointed in Mr. Lopez, whom he said has used politics in his selection of judges, and is calling for the judicial selection system to be replaced with one that is more based on merit. He said he had no idea whether Mr. Lopez’s daughter was qualified to be a judge, but said that if she is qualified, then her reappointment is merited.

“That, in and of itself, is not the issue,” he said. “If she got access to the position specifically because she was related to a politician and if she was able to be reappointed because she is related to a politician and her qualifications are secondary, that is a problem and that is our concern,” he said.

A Democratic district leader from Park Slope who has been a critic of the system to select Supreme Court justices, Alan Fleishman, said yesterday it doesn’t matter who a prospective judge is, that “if you don’t have political connections, you won’t become a judge.”

Mr. Lopez declined to comment yesterday.

A spokesman for Mr. Paterson, Errol Cockfield, wrote in an email message that Mr. Lopez’s daughter was reviewed by a screening committee, which found her to be highly qualified. “It would be extraordinary, if not unprecedented, for a Governor to refuse to re-nominate a highly-qualified individual who has been serving on a court, simply because her father happens to be an elected official,” he wrote. Governor Pataki first nominated Ms. Summer to fill out a vacancy for one year beginning in 2006.