Without apology, Santorum grounds his concept of family in what he properly identifies as a "natural" form. Even though he speaks of the "traditional" family, he recognizes that the natural or nuclear family is something prior to tradition. As a Roman Catholic, Santorum grounds this in the natural law. In so doing, he raises an issue that should attract broad Christian consensus. He correctly asserts that liberals see nature as far too confining and thus the enemy of freedom. "Liberals believe that the traditional family is neither natural nor vital, and that it's an antiquated social convention which has not only outlived its usefulness, but is now inherently discriminatory and repressive towards legitimate alternative 'families,'" Santorum reflects.

Why would the senator tie his social vision to such an arbitrary definition of family? He answers that question clearly: "Every known society has some form of marriage. And it's always about bringing together a male and a female into the kind of sexual union where the interests of children under the care of their own mother and father are protected. Marriage is the word for the way in which we connect a man, a woman, and their children into one loving family. It represents our best attempt to see that every child receives his or her birthright: the right to know and be known by, to love and to be loved by, his or her own father and mother."

Santorum recognizes that many families fail to live up to this vision. Nevertheless, he rightly insists that nothing can replace the family. When advocates for same-sex marriage attempt to redefine marriage as an institution, they are merely articulating a vision of what Santorum calls "liberal marriage." As he sees it, "the 'right' of homosexuals to 'marry' one another is a logical result of what must happen to the definition of marriage if we view society as composed of nothing but abstract, autonomous individuals, rather than of men and women with their given natures. Abstract individuals, after all, are completely interchangeable and completely 'free' to define who and what they are. To the liberal mind, therefore, there is no 'rational basis' for limiting marriage only to people of opposite sexes . . . . Our village elders now declare that those holding to the traditional understanding of marriage are simply irrational."

Of course, Santorum is a legislator, and he understands the role of law as an instrument for teaching the young. "Just imagine two or three generations from now, if we legalize same-sex marriage today, what young adults will understand about marriage," he suggests. "Keep in mind that they will have been raised in a society that considers marriage nothing more than a romantic and sexual coupling between men and men, women and women, and men and women. The law will have declared it so, the centers will have been pressured into silence, and public schools will embrace and teach same-sex marriage as the law of the land. Laws have meaning, and therefore, laws teach. When something is legal it has the presumption that it is moral and right. If the sexual unions of men with men and women with women have equal dignity with the union of men and women, then marriage cannot be understood as having anything intrinsically to do with children. Society will teach the next generation that marriage is a self-centered endeavor primarily about adult satisfaction, not children's well-being."