Eve Tushnet wonders why marriage is the only area of contemporary politics in which tradition is used explicitly as a justification:
Two things have happened to contemporary marriage which all but compel traditionalist rhetoric in a non-traditionalist culture. First, one of marriages core purposes has been suppressed in public discourse. Marriage developed in major part to regulate sex between men and womento regulate it not solely within marriage but before marriage. The idea that marriage as an institution should regulate whether the unmarried have sex used to be obvious. Its not that everyone actually abstained, as the bawdy songs show! But the cultural expectation was that premarital chastity could be demanded, defended, held up as social necessity and religious virtue, and its opposite punished (as in the sadder bawdy songs) or wryly rejected (as in the funnier ones).
Ten minutes conversation with people in their teens or twenties, anywhere from Main Street to Martin Luther King, Jr. Boulevard, will make clear that the exact opposite of this perspective is now as obvious as the older one used to be. Premarital sex is not only practiced but assumed, and often valorized. (You should live together before marriage; dont be stupid!)