SAN FRANCISCO – A Boy Scout group argued to the California Supreme Court yesterday that the city of Berkeley violated the Constitution by ending the youth organization’s six decades of free access to the city’s marina in a dispute over the Boy Scouts’ exclusion of gays and atheists.

“You cannot exact a surrender of constitutional rights as a condition of providing a public benefit,” a lawyer for the scout group, Jonathan Gordon, told the judges during more than an hour of oral arguments. “It interferes with the Boy Scouts’ speech. It interferes with their ability to convey a different message.”

An attorney for the city, Manuela Albuquerque, said there was no requirement that the city give support to groups that act in ways antithetical to Berkeley’s values. “We don’t want to use our money to fund discriminatory actions,” she said.

Ms. Albuquerque warned that a victory for the scouts would open the city’s coffers on a “first-come, first-served” basis to groups like the Ku Klux Klan.

The case heard yesterday involves a marine scouting troop, known as Sea Scouts, whose ships have been moored at the Berkeley marina since 1945. In 1997 the City Council passed a resolution forbidding the use of city funds to subsidize organizations that violate the city’s anti-discrimination policies, which bar consideration of sexual orientation or religious belief.

During negotiations that followed, the Sea Scout troop sent a carefully worded letter to the city, promising not to violate Berkeley city policies. However, a pledge of non-discrimination in the letter conspicuously omitted sexual orientation.

In 1999 Sea Scout leaders brought suit against the city, but a county judge threw the case out. A California appeals court upheld that decision.

In 2000, amidst the legal maneuvering in California, the U.S. Supreme Court ruled that a New Jersey law against discrimination in public accommodations could not be used to force the admission of a scoutmaster who is openly gay.

Mr. Gordon said yesterday that the Berkeley troop has never discriminated against anyone for being gay or an atheist because the issue has never arisen. The troop has also said it doesn’t inquire into its members’ sexual orientation. However, the lawyer said the local chapter could not expressly disavow the national organization’s policies and would have to comply if it ordered someone out.

“We’re bound by what the Boy Scouts tell us we have to do,” Mr. Gordon said under questioning by the judges yesterday. “If the Boy Scouts come down on us we would have to exclude that person.”

The court’s chief justice, Ronald George, noted that the local troop could lose its liability insurance if it gave up its affiliation with the national association.

Ms. Albuquerque told the judges that the letter from the troop did not indicate compliance with the city’s rules. “That is a ‘don’t-ask, don’t-tell’ policy. It simply begs the question,” she told reporters.

Both sides in the case conceded that the city’s marina is not a public forum, as is a public park or city square. “Getting on a boat is not basically part of First Amendment rights,” Judge George said.

Ms. Albuquerque argued that U.S. Supreme Court precedents establish the government’s right to condition benefits on compliance with anti-discrimination policies. She pointed to a 1983 decision upholding the federal government’s right to deny a tax exemption to a conservative South Carolina school, Bob Jones University, because of its policies against interracial marriage and dating. In the following year, the Supreme Court used similar reasoning to uphold the government’s right to enforce rules against gender discrimination.

The court did not rule yesterday and none of the justices stated a clear position on the Sea Scouts’ case. Many of the judges appeared receptive to Berkeley’s claim that it could limit its subsidies to groups that comply with the city’s rules. However, the Scouts’ allegation that they were pursued and punished because of animus toward their views had more resonance with the court.

Judge Marvin Baxter said it was possible that the decision to enforce the marina policy against the scouts was “pretextual.”

In an amicus brief, the Boy Scouts of America noted that other groups that receive the free berthing privilege cater to women, teenagers, or the disabled, and could therefore be in violation of the anti-discrimination rules.

Judge Baxter also indicated he was troubled that the case was thrown out before the Scouts had a chance to prove they were targeted by city officials looking to send a message. “Why shouldn’t a jury be entitled to consider all the evidence?” the judge asked.