The U.S. Supreme Court case Mackenzie v. Hare et al., Board of Election of San Francisco in 1915 revolved around the issue of women's suffrage and citizenship rights. Ethel Mackenzie, a British-born woman who had married an American man, challenged the constitutionality of a law that automatically revoked her U.S. citizenship upon marrying a non-U.S citizen and subsequently denied her right to vote despite residing in California where women were allowed to vote since 1911. The court ruled against Mackenzie, upholding the Expatriation Act of 1907 which stated that any American woman who married a foreigner would take on his nationality status regardless if he was eligible for naturalization or not; thus affirming that she lost her US citizenship when she got married and therefore could not claim voting rights as an American citizen.

In the dissenting opinion for Mackenzie v. Hare, Justice Hughes argued that the law in question violated a woman's constitutional rights by automatically revoking her citizenship upon marrying a foreigner. He contended that this action was not within Congress' power to regulate naturalization because it did not involve an individual voluntarily renouncing their citizenship or becoming naturalized in another country. Instead, he viewed it as an involuntary forfeiture of one’s nationality without due process of law and thus unconstitutional under the Fourteenth Amendment. Furthermore, he pointed out that men were not subjected to similar treatment when they married foreign women which made this legislation discriminatory based on gender.