To rule last week that it was constitutional for Nevada to bar gay couples from getting married, U.S. District Judge Robert Jones had to determine that there was a “reasonably conceivable state of facts that could provide a rational basis” for the state to reserve marriage to straight couples. Here’s what he came up with: Marriage is important to maintaining a stable society, and if it is expanded to include gays, “it is conceivable that a meaningful percentage of heterosexual persons would cease to value” marriage because “they no longer wish to be associated with the civil institution as redefined.” One of the benefits of a court case is it allows the airing of most of the arguments that exist for and against gay marriage. (The exception is opposition based on religious conviction. Because of the separation of church and state in the Constitution, that’s not a basis the government can cite for barring gay unions.) This is particularly true of “equal protection” challenges—those claiming that a law violates the Constitution’s guarantee of equal treatment—that require the government to show at least a “rational basis” in defense of the law.