In recent years, marriage has weakened, with serious negative consequences for society as a whole. Four developments are especially troubling: divorce, illegitimacy, cohabitation, and same-sex marriage. The purpose of this document is to make a substantial new contribution to the public debate over marriage. Too often, the rational case for marriage is not made at all or not made very well. As scholars, we are persuaded that the case for marriage can be made and won at the level of reason. Marriage protects children, men and women, and the common good. The health of marriage is particularly important in a free society, which depends upon citizens to govern their private lives and rear their children responsibly, so as to limit the scope, size, and power of the state. The nation's retreat from marriage has been particularly consequential for our society's most vulnerable communities: minorities and the poor pay a disproportionately heavy price when marriage declines in their communities. Marriage also offers men and women as spouses a good they can have in no other way: a mutual and complete giving of the self. Thus, marriage understood as the enduring union of husband and wife is both a good in itself and also advances the public interest.