This past spring, as part of my work teaching international relations, I oversaw a team of students assigned to create a first-of-its kind, comprehensive report on the status of women in the United States. Four of the students working on the project were from other countries—Afghanistan, Bolivia, Nepal, and Nigeria—and many of the findings pierced their idea of America as a nation that protects women and girls. One issue stood out among the rest: child marriage. USAID officials have declared child marriage a human-rights violation. Last year, the agency laid out a “roadmap” to end child marriage worldwide by 2030. And yet only 10 U.S states ban marriage under age 18 without exception. Five states have no minimum age of marriage as long as parental and/or judicial consent is given. The rest of the states allow child marriage with age limits—usually 16 to 17, though sometimes younger—as well as parental and/or judicial consent. Congress has set some limits on child marriage, but because marriage is regulated at the state level, the United States has no …