One of the pressing questions of our day is whether the laws of governments dedicated to liberty may regulate sexual behavior by legislating sexual morality. Although contemporary liberal theorists often argue that it is illegitimate to regulate private sexual behavior, the early modern liberal theorist, Montesquieu, takes the opposite view. In Spirit of the Laws, he argues that governments dedicated to liberty ought to legislate sexual morals according to the standards of natural laws and rights.
That Montesquieu is a natural law and natural rights thinker is itself a debated claim. Chapter two argues that Montesquieu appeals to a non-perfectionist, justice based, liberty oriented, natural law and natural rights theory. On the subject of his sexual morals, his essential view is that sexual behavior should be reserved for marriage between one man and one woman, and that sexual practices outside of marriage are violations of natural laws, rights, and the political and civil needs of free societies.
In order to understand how he legislates sexual morals, one must first answer which of the three government forms most conforms to the requirements of natural laws and rights. Chapter three establishes that monarchy is that form by appealing to his teaching that the condition, moral character, and liberty of women in a given society are key indicators of the degree of liberty and morality generally practiced there. Monarchy is the most hospitable to the female’s nature, natural laws and rights.
Chapter four studies how the civil laws of Montesquieu’s monarchy regulate marriage and procreation, divorce, adultery, homosexuality, polygamy, and modesty, and shows that his laws do regulate sexual behavior according to the requirements of his natural law, natural rights sexual morality.
The final chapter assesses the relative merits of Montesquieu’s position by comparing his recommendations to those of the contemporary liberal theorist, Richard Posner, who also aims to show how the laws can regulate sexual behavior, but from a morally neutral standpoint. Montesquieu’s position is internally more coherent, persuasive, and desirable for thinking about how the laws of a government dedicated to liberty ought to regulate sexual behavior.