SAN FRANCISCO — Municipal agencies may provide tax-exempt bonds to a religious school — as long as its curriculum includes secular classes, the California Supreme Court ruled Monday.

The 4-3 decision reverses an earlier ruling and hands a victory to three Christian schools in Southern California.

In 2002, Oaks Christian School, California Baptist University and Azusa Pacific University wanted to construct cafeterias, a mail center and athletic facilities using bonds from “joint power authorities.”

California has more than 350 joint power authorities — public consortiums that provide tax breaks to institutional investors who fund public interest projects with low-interest loans. The municipal groups often finance residential housing and schools.

Critics complained the tax-free municipal bonds violated church-state separation in California’s Constitution.

Justice Joyce Kennard, a Republican appointed by Gov. George Deukmejian in 1989, said the bonds didn’t violate state law or the First Amendment of the U.S. Constitution.

Joint power authorities could fund religious schools if they “offer a broad curriculum in secular subjects” and provide classes that are “neutral with respect to religion,” she wrote.

“The straightforward assessment for the trial court to make is whether the academic content of a religious school’s course in a secular subject such as math, chemistry or Shakespeare’s writings is typical of that provided in nonreligious schools,” Kennard wrote, sending the case back to California’s Court of Appeal.

Chief Justice Ronald George and Justices Marvin Baxter and Carol Corrigan agreed.

Dissenting Justice Ming Chin said the majority’s “hopelessly vague” opinion failed to quantify the number of secular classes needed to allow a religious school to use municipal bonds. The majority opinion said nonreligious offerings should be “sufficiently broad.”

Chin argued the three schools were “organized primarily or exclusively for religious purposes,” so any new projects would aid “religious indoctrination.”

About 65 percent of students at Oaks Christian School, a middle and high school in Westlake Village, were Christian in 2001. Students sign a statement of faith emphasizing “Biblical goals.”

California Baptist University in Riverside reserves 51 percent of its faculty positions for Baptists.

Azusa Pacific University in Azusa is an evangelical school requiring undergraduates to complete 120 hours of “student ministry assignments.”

“The proposed bond financings would have the direct, immediate and substantial effect of advancing religion,” Chin wrote, joined by Justices Kathryn Mickle Werdegar and Carlos Moreno.

The case is California Statewide Communities Development Authority v. All Persons Interested in the Matter of the Validity of a Purchase Agreement, S124195.