For most of the twentieth century, the courts applied a standard of restrained review to laws involving gender differentiation. They insisted only that lawmakers provide some sort of reasonable explanation for treating men and women differently in the laws that they passed. Most commonly, this "reasonable" explanation drew upon now outdated ideas about women's physical, intellectual, and psychological character. For example, in 1873 the Supreme Court upheld an Illinois law denying women the right to practice law because "…the civil law, as well as nature itself, has always recognized a wide difference in the respective spheres and destinies of man and woman. Man is, or should be, woman's protector and defender. The natural and proper timidity and delicacy which belongs to the female sex evidently unfits it for many of the occupations of civil life. The constitution of the family organization, which is founded in the divine ordinance, as well as in the nature of things, indicates the domestic sphere as that which properly belongs to the domain and functions of womanhood."32
The Court used similar logic in upholding a Denver city ordinance that outlawed alcohol sales to women and a Michigan law that placed severe restrictions on women seeking work as bartenders. Somewhat ironically, the same sexist logic also lay behind the Court's affirmation of various laws that protected women in the workplace. Maximum hours and minimum wage laws for women were upheld by the Court because a "woman's physical structure and the performance of maternal functions place her at a disadvantage which justifies a difference in legislation in regard to some of the burdens which rest upon her."33 As late as 1961, the Court allowed women to opt out of jury service because "despite the enlightened emancipation of women . . . woman is still regarded as the center of home and family life."34
In short, a full century after the ratification of the Fourteenth Amendment, the courts were still applying a "restrained review" to laws differentiating between men and women. If the courts could find any "reasonable" explanation for different treatment (no matter how unreasonable we might now consider that explanation today) the law would stand. It took Oklahoma's dual drinking age law to shake, not stir, the Court out of this legal inertia.