Federal district judge Michael McShane issued a ruling striking Oregon’s state constitutional ban same-sex marriage today. The text of the opinion is available here.

Like last week’s similar decision by a federal court in Idaho, today’s ruling is part of a growing trend of state and federal court invalidations of laws banning same-sex marriage since the Supreme Court decided United States v. Windsor last year. I discussed the significance of that trend in my post on the Idaho ruling. See also this analysis by Margo Schlanger of the University of Michigan.

Judge McShane based his decision on the ground that “Oregon’s marriage laws discriminate on the basis of sexual orientation without a rational relationship to any legitimate government interest” and therefore cannot withstand even minimal “rational basis” scrutiny. I am skeptical of that argument for reasons noted by co-blogger Eugene Volokh here.

McShane rejected the sex discrimination argument against gay marriage bans for almost exactly the same reason as the Idaho decision did. I criticized that sort of reasoning here and here.

Overall, I think today’s decision reaches the right result, but based on the wrong reasoning.

Today’s ruling also raises a minor ethical controversy because Judge McShane is openly gay, and recently rejected a request by the National Organization for Marriage that he recuse himself from the case on that basis. McShane is right on that point. If female judges need not recuse themselves from sex discrimination cases or black judges from race discrimination cases, gay and lesbian judges need not recuse themselves from cases alleging discrimination against their groups either.

UPDATE: In this post, I analyzed the strengths, weaknesses, and potential implications of different rationales for striking down laws banning same-sex marriage, including the ones considered in the Oregon case.

UPDATE #2: I failed to notice that co-blogger Dale Carpenter put up a post about this ruling just before I did. I agree with most of what he said. I am going to leave this one up because it contains some points and links that Dale did not include.