In her book Public Vows: A History of Marriage and the Nation, Nancy F. Cott explains at length how deeply intertwined marriage and public government have been in America. From the beginning marriage has been treated not as a religious institution, but as a private contract with public implications:
Although the details of marital practice varied widely among Revolutionary-era Americans, there was a broadly shared understanding of the essentials of the institution. The most important was the unity of husband and wife. The "sublime and refined...principle of union" joining the two was the "most important consequence of marriage," according to James Wilson, a preeminent statesman and legal philosopher.
The consent of both was also essential. "The agreement of both parties, the essence of every rational contract, is indispensably required," Wilson said in lectures delivered in 1792. He saw mutual consent as the hallmark of marriage — more basic than cohabitation.
Everyone spoke of the marriage contract. Yet as a contract it was unique, for the parties did not set their own terms. The man and woman consented to marry, but public authorities set the terms of the marriage, so that it brought predictable rewards and duties. Once the union was formed, its obligations were fixed in common law. Husband and wife each assumed a new legal status as well as a new status in their community. That means neither could break the terms set without offending the larger community, the law, and the state, as much as offending the partner.
Early Americans' understanding of marriage was closely tied to their understanding of the state: both were seen as institutions which free individuals entered into voluntarily and thus could also exit voluntarily. The basis of marriage was not religion, but the wishes of free, consenting adults.
