The most interesting question in the upcoming trial of Clarence Norman Jr. trial won’t be the fate of the former assemblyman and political boss.

What is likely to receive the most scrutiny is a theory held by Brooklyn’s district attorney: that the concessions party leaders ordinarily demand from candidates who want the party imprimatur amount to criminal extortion.

The trial will focus on Norman’s alleged demand that two judicial candidates spend their campaign funds at consulting and printing businesses that he approved. These demands were allegedly made over a table at the Park Plaza Restaurant, a well-known diner near the courthouses in Brooklyn.

The issues this trial presents are likely to appeal to an audience wider than the usual courthouse crowd. The trial is of particular interest this year, as lawmakers in Albany are set to choose a system for selecting state trial judges.

With the state Senate expected to throw its support behind a bill requiring all state judges to go through an open primary, the upcoming trial could be used as an argument for proponents of an appointment system. It is expected to demonstrate how judicial candidates, like all political candidates, often come to depend a great deal on party organizations and donors when campaigning to win a primary.

“One of the things we hear from time to time is that this is a Brooklyn problem,” the executive director of the Fund for Modern Courts, Dennis Hawkins, said yesterday of the corruption allegations. “Indeed, it may be. But wherever there is a system that requires judges to run for election, it seems that the possibility of corruption exists.”

“To a certain extent, the upcoming Norman trial will talk about those issues,” Mr. Hawkins said.

Jury selection is set to begin on Tuesday and could take a week.

The trial is Norman’s fourth. He has been convicted twice, but was acquitted at his most recent trial. At that trial, he faced allegations that he had filed expense reports for bills he did not incur while an assemblyman. Norman faces between two and six years in prison for his prior convictions, although he has not yet been sentenced.

The investigation by Brooklyn’s district attorney, Charles Hynes, dates back to at least 2002 and began following the arrest of judge on bribery charges. While Mr. Hynes has charged several other judges with crimes, he has yet to prove that judgeships are bought and sold in Brooklyn — the original goal he set for himself. Norman, who had the reputation as a kingmaker of Brooklyn judges, has been at the center of his inquiry.

“You could hold a hundred trials,” the president of New York Civic, Henry Stern, said.

Indeed, that may be Mr. Hynes’s intent. Norman, who has been replaced as party chairman, could be newly indicted on allegations that he took an envelope of cash in return for a judgeship, the Village Voice reported last week.

The witnesses expected to testify against Norman include a sitting housing court judge, Marcia Sikowitz, and the former executive director of the Brooklyn Democratic organization, Jeffery Feldman.

The prosecution’s case is largely based on Norman’s alleged dealings with Judge Sikowitz and a referee in state court Karen Yellen for several months in 2002. At the time, both were candidates for Civil Court positions and met with Norman to discuss the support that the party organization could provide. The price tag of a strong countywide campaign is more than $100,000, and Norman directed that the candidates were to use that money to hire consultants and businesses that he named to carry out the required mailings, advertisements, and consulting work, prosecutors allege.

Whether that amounts to a criminal larceny, coercion, and conspiracy, as prosecutors claim, remains unclear.

Both candidates lost in the Democratic primary that year.

Originally, Mr. Feldman, who ranked second in the county organization, had also been charged. But last year he agreed to cooperate with prosecutors and charges against him were dismissed. Since making that decision, he has been replaced as the county organization’s executive director by Derek Davis. Mr. Davis is a former legislative assistant to the current county chairman, Assemblyman Vito Lopez.