The clubhouse politics of Brooklyn will come under the scrutiny of the U.S. Supreme Court, which yesterday accepted a case about whether New York’s system of selecting state trial judges is unconstitutional.

The task before the Supreme Court is to decide whether New York’s political organizations, particularly the Brooklyn Democrats, were so arbitrary in endorsing certain candidates for the bench that the constitutional rights of voters and other candidates were violated.

The case is being brought by a judicial candidate, Margarita Lopez Torres, who says the leader of the Brooklyn Democratic organization shut her out from participating in the annual convention by which the organization nominated its candidates for New York’s basic trial court, the state Supreme Court.

The implications of the decision in the case by the federal high court could reach beyond New York to any state where the law allows for parties to use conventions to nominate candidates for any public office, a lawyer for the Republican National Committee, H. Christopher Bartolomucci, wrote in a brief to the U.S. Supreme Court.

Mr. Bartolomucci, of Hogan and Hartson, wrote that a Supreme Court decision in favor of the candidate could threaten the First Amendment rights of political parties to endorse candidates.

“The convention that selected Franklin Roosevelt to be the Democratic nominee for the presidency, that would somehow have been unconstitutional taking this to its logical conclusion,” an attorney who represents the city and state associations of New York Supreme Court judges in the case, Joseph Forstadt of Stroock & Stroock & Lavan, said.

But lawyers for the judicial candidate say the case is unlikely to affect election law outside of New York, given that the state is the only one in the nation to nominate state judges through a convention system. The plaintiffs have won two lower court decisions and had asked the U.S. Supreme Court not to take the case, which is on appeal from the 2nd U.S. Circuit Court of Appeals.

The possibility that the U.S. Supreme Court will overturn the 2nd Circuit’s decision is expected to create a pause in the debate in Albany over how to change the way New York selects its state judges. Governor Spitzer, Mayor Bloomberg, and Chief Judge Judith Kaye have all pitched proposals to the Legislature, ranging from constitutional amendments to comparatively modest tinkering with the convention system currently under challenge.

In New York, local Democratic and Republican organizations hold competing conventions in September of each year for the purpose of bestowing party nominations on candidates for 14-year terms to the state Supreme Court. Although local delegates are elected for the purpose of bestowing the nomination, critics of the system have long argued that delegates defer entirely to the local party leader, who, in effect, becomes the local judgemaker.

The plaintiffs say that this current system fails to live up to the state constitution, which mandates that judges will be chosen by the electorate.

In the 2006 decision, Judge Chester Straub of the 2nd Circuit described the system by saying, “through a Byzantine and onerous network of nominating phase regulations employed in areas of one-party rule, New York has transformed a de jure election into a de facto appointment.”

The judicial nominating conventions, as they are called, trace their beginnings to 1921, when the Legislature chose them rather than primary elections. The reasoning was that competitive primary elections would force judges to solicit campaign donations from the lawyers whose cases they heard.

The case is brought on behalf of Ms. Lopez Torres, who is now a judge in surrogate court in Brooklyn. Although she had proven her ability to win lesser judgeships in the past, the Brooklyn Democratic organization has declined repeatedly over the last decade to nominate her for a state Supreme Court judgeship. Judge Lopez Torres claims the party organization is hostile to her because in 1992 she refused to hire a law secretary whose resume was passed on to her by two Brooklyn assemblymen, Clarence Norman Jr., and Vito Lopez.

Judge Lopez Torres says that since then party leaders, such as Norman, then the chairman of the county organization, have opposed her candidacy, depriving her of the opportunity to even address the elected delegates at the 2003 nominating convention in Brooklyn. Norman has since been convicted of felony campaign finance violations.

“The convention functions in such a way that candidates who are well qualified and have strong backing from the rank and file of their political parties were nonetheless shut out from the political process,” a lawyer for Judge Lopez Torres, James Sample of the Brennan Center of Justice at New York University, said.

But lawyers for organizations who have voluntarily joined the suit as defendants say the federal courts are making a mistake in turning Judge Lopez Torres’ inability to secure the Democratic nomination into a constitutional issue.

“It’s no surprise that party leaders have influence and no one has ever thought that was unconstitutional,” Mr. Bartolomucci, who wrote the brief for the RNC, said.

Mr. Forstadt, who represents current state judges, said that in elections “there are always problems and somebody is always disappointed.”

Mr. Forstadt said that if Judge Lopez Torres wins at the Supreme Court he expected that one result would be an increase in federal lawsuits from “disappointed candidates” who challenge the political process resulting in their defeat.

The lawsuit pits Judge Lopez Torres against the state’s Board of Elections, which was represented by then Attorney General Spitzer. The New York County Democratic Committee and the New York Republican State Committee as well as the associations of sitting state judges have joined the lawsuit as defendants. Representing the defendants are a former solicitor general, Theodore Olson, and a well-known Supreme Court advocate, Carter Phillips of Sidley Austin.

The U.S. Supreme Court did not indicate when it will hear oral arguments in the case.