SAN FRANCISCO — Taking a narrow approach in deciding the blockbuster challenge to California’s ban on gay marriage, a split panel of the Ninth Circuit U.S. Court of Appeals on Tuesday found Proposition 8 unconstitutional.

Writing for the majority, Judge Stephen Reinhardt said the ban runs afoul of the Equal Protection Clause, serving no purpose other than “to lessen the status and human dignity” of gays in California who could legally marry for a few months before the 2008 vote on Prop 8. The Constitution, Reinhardt wrote, citing the U.S. Supreme Court’s Romer v. Evans, does not allow for “laws of this sort.”