Commenting on the changes that the institution of marriage has undergone over the last century, legal scholar John Witte observed, “The early Enlightenment ideals of marriage as a permanent contractual union designed for the sake of mutual love, procreation and protection is slowly giving way to a new reality of marriage as a ‘terminal sexual contract’ designed for the gratification of the individual parties.”

Certain grim statistics seem to support Witte’s statement: About two and a half million Americans divorce each year, and nearly 50 percent of marriages in the United States end in divorce or separation within fifteen years. Moreover, the incidence of divorce increased more than sixfold since the early twentieth century. Many marriage supporters argue that the women’s rights movement in the 1960s and 1970s contributed to the decline of the...