What do we think about permitting "homosexual marriage" in society? Even if homosexuality is immoral, shouldn't "homosexual marriage" be legal? After all, church and state are supposed to be separate, and you can't legislate morality.

First, we agree that homosexual acts are immoral. Scripture teaches this (Genesis 18:20-21, 19:4-5; Leviticus 18:22, 20:13; 1 Corinthians 6:9-11; Jude 7). Natural law teaches this (Romans 1:26-27). Second, we agree that church and state are distinct institutions, each divinely ordained for its own special role (AC XVI; Apol. XVI). This does not, however, mean they are completely separate, as if the one should never have anything to do with the other. In the case of the "homosexual marriage" debates, the church should teach both God's moral law (so that the Law may work repentance) and also Christ's gospel of forgiveness (since only the Gospel can comfort sinners with forgiveness, new life, and eternal salvation). The state, for its part, should pass laws to protect marriage--the lifelong union of a man and a woman. The Lutheran Confessions explicitly call upon the state to employ "the strictest laws" for the protection of marriage, lest the sins of Sodom and Gomorrah lead to social and political decline. (Apol. XXIII, 54-55) This does not "legislate morality" any differently than other laws based on a natural law, such as the prohibition of stealing, which protects the natural law right to property (cf. Apol. XVI, 11).