Virginia Postrel weighs in on sodomy laws with the equal protection argument:
The Georgia sodomy law in Bowers did not distinguish between homosexual sodomy and heterosexual sodomy. Thus, as one of the dissents pointed out, it was a mystery why the majority went off on homosexuals. While the plaintiff in that case was, in fact, gay, under the law at issue, it made no difference. It was as if the majority were to decide, given an Asian defendant in a murder case, that they would craft a rule for Asian murder, or Asian Miranda rights, or Asian due process.
The Texas law throws open that bizarre aspect of Hardwick. Texas permits heterosexuals to engage in all the sodomy they want, and prohibits it only for lesbians and gay men. This brings the equal protection clause into play. One of the fundamental aspects of our democracy is that a majority may not impose on a minority rules it does not impose on itself, unless there is a good reason. While the level of scrutiny a court will give to such laws varies, at the very least the majority must have a rational basis for imposing rules on minorities it does not choose to impose on its own members. Thus, the court may very well decide that, while states may continue to prohbit sodomy despite the liberty and privacy jurisprudence, they cannot prohibit it for one group and not for another — a state sodomy law must apply to all citizens or none under the equal protection clause.
Well. . . no. As far as I’m aware, homosexuals aren’t a protected class. The Constitution precludes state discrimination on the basis of race, so “Asian murder” laws would be obviously unconstitutional. And, presumably, homosexual sodomy would be illegal for heterosexuals, too, under Texas law.
Now, again, I think these laws are a bad idea. And I’m not sure they survive a rational basis test. But let’s not start with the presumption that the law currently treats sexual orientation in the same way it treats race or even gender.
Update (18:00): Chris mentions a possible counter-precedent in his Comments below. Romer v Evans occurred to me, but since they didn’t overturn Bowers v Hardwick, I don’t think it qualifies. Indeed, Scalia points out that inconsistency in his dissent.
The decision in Romer basically relies on a rational basis argument:
The primary rationale the State offers for Amendment 2 is respect for other citizens’ freedom of association, and in particular the liberties of landlords or employers who have personal or religious objections to homosexuality. Colorado also cites its interest in conserving resources to fight discrimination against other groups. The breadth of the Amendment is so far removed from these particular justifications that we find it impossible to credit them. We cannot say that Amendment 2 is directed to any identifiable legitimate purpose or discrete objective. It is a status based enactment divorced from any factual context from which we could discern a relationship to legitimate state interests; it is a classification of persons undertaken for its own sake, something the Equal Protection Clause does not permit. “[C]lass legislation . . . [is] obnoxious to the prohibitions of the Fourteenth Amendment . . . .” Civil Rights Cases, 109 U. S., at 24.
We must conclude that Amendment 2 classifies homosexuals not to further a proper legislative end but to make them unequal to everyone else. This Colorado cannot do. A State cannot so deem a class of persons a stranger to its laws. Amendment 2 violates the Equal Protection Clause, and the judgment of the Supreme Court of Colorado is affirmed.
They specifically didn’t overturn Bowers and specifically declined to create a protected class. But they did take something of a half step in that direction.