The Volokh Conspiracy
Mostly law professors | Sometimes contrarian | Often libertarian | Always independent
In Friday's Perez v. City of Roseville decision, the Ninth Circuit held that Lawrence v. Texas covers adulterous sex:
Lawrence makes clear that the State may not stigmatize private sexual conduct simply because the majority has "traditionally viewed a particular practice," such as extramarital sex, "as immoral."
The court didn't consider that adulterous sex, which involves the breaking of a vow made to the other spouse, might not be covered by the it's-just-consenting-adults logic of Lawrence. (Extramarital sex with the consent of the other party, as in an "open marriage," may be a separate matter.)
As you might gather, Perez didn't involve criminal prosecutions for adultery, which appear very rare in the U.S. except for the military justice system, and even there are allowed only when the adultery "was to the prejudice of good order and discipline in the armed forces or was of a nature to bring discredit upon the armed forces," for instance when it involved a fellow service member's spouse. Nor did the case involve civil liability, for instance under the torts of criminal conversation or alienation of affections, which are still recognized in several states, and fairly regularly lead to liability in North Carolina (see, e.g., Malecek v. Williams (N.C. App. 2017)).
Rather, in Perez, a police department fired a police officer, who then argued the firing was based in part on the officer's adultery. The Ninth Circuit concluded that, if that was true, the firing would violate the officer's constitutional rights unless the adultery "negatively affects on-the-job performance or violates a constitutionally permissible, narrowly tailored regulation"—this would be a pretty similar test to that used for firings based on other constitutional rights, such as Free Speech Clause rights.
The Ninth Circuit relied on a 1983 Ninth Circuit precedent that had taken a similar view, though that case hadn't discussed whether adultery might be different enough from other sexual conduct to be constitutionally unprotected. And the Ninth Circuit acknowledged that its position differed from that taken by post-Lawrence Fifth and Tenth Circuit cases dealing with similar matters. If the city petitions the Supreme Court, there's a good chance, I think, that the Court will agree to hear the case (though I can't speak with any confidence about how the Court would resolve it).