The surprising story of how declining marriage rates are driving many of the country’s biggest economic problems. In The Two-Parent Privilege, Melissa S. Kearney makes a provocative, data-driven case for marriage by showing how the institution’s decline has led to a host of economic woes—problems that have fractured American society and rendered vulnerable populations even more vulnerable. Eschewing the religious and values-based arguments that have long dominated this conversation, Kea...