The views which contributed to rape laws not being applicable in marriage can be traced, at least partially, to the 17th century, to English common law, which was exported to the US: the views of Sir Matthew Hale, a 17th-century English jurist, published in The History of the Pleas of the Crown (1736), stated that a husband cannot be guilty of the rape of his wife because the wife "hath given up herself in this kind to her husband, which she cannot retract" (this would remain law in England and Wales for more than 250 years, until it was abolished by the Appellate Committee of the House of Lords, in the case of R v R in 1991). The strong influence of conservative Christianity in the US may have also played a role: the Bible at 1 Corinthians 7:3-5 explains that one has a "conjugal duty" to have sexual relations with one's spouse (in sharp opposition to sex outside marriage which is considered a sin) and states that "The wife does not have authority over her own body, but the husband does. And likewise the husband does not have authority over his own body, but the wife does. Do not deprive one another (...)" - and this is interpreted by some conservative religious figures as rejecting to possibility of marital rape.
Prior to the mid-1970s marital rape was not a crime. Traditional rape laws in the US defined rape as forced sexual intercourse by a male with a "female not his wife", making it clear that the statutes did not apply to married couples. The 1962 Model Penal Code stated that "A male who has sexual intercourse with a female not his wife is guilty of rape if: (...)". In 1993, North Carolina became the last state to remove the spousal exemption. On July 5, 1993, marital rape became a crime in all 50 states, under at least one section of the sexual offense codes.
In some states, notably New York - in People v. Liberta 1984  - the courts had been involved in striking down the marital exemption as unconstitutional. The decision of the New York Court of Appeals, delivered by judge Sol Wachtler, stated that "a marriage license should not be viewed as a license for a husband to forcibly rape his wife with impunity. A married woman has the same right to control her own body as does an unmarried woman".