Endorsement tests

Interesting post here about the relationship between legal rights, moral sanction, and equal treatment. Could one argue that same-sex marriage bans based on religious, traditional views of marriage (as opposed to some measurable social harm) might violate O'Connor's endorsement test and thus the First Amendment? Defining marriage to be only what conservative sects of some religions say it is seems to convey "a message that religion is 'favored,' 'preferred,' or 'promoted' over other beliefs." Allegheny County v. ACLU.