Between 1990 and 1995, Eskridge represented a gay couple seeking a marriage license in Washington, D.C. Like all the other early same-sex marriage cases, this one did not prevail, but for the first time in American history, one judge, John Ferren of the DC Court of Appeals, wrote an opinion finding discrimination against same-sex couples to be unconstitutional (
Dean v. District of Columbia, 653 A.2d 307 (D.C. 1995)). In 1996, Eskridge wrote his pathfinding book
The Case for Same-Sex Marriage (Free Press 1996), arguing that marriage discrimination against LGBT couples violated both their fundamental right to marry and their equal protection right to be free of invidious state discrimination. The book was criticized at the time, with West Virginia US Senator
Robert Byrd quoting extensively from it in his speech supporting the
Defense of Marriage Act in 1996, an overwhelming, bipartisan rebuke to the marriage movement. Ultimately, many state courts and the US Supreme Court (
Obergefell v. Hodges (2015)) adopted these arguments in favor of gay marriage. As Judge Posner put it in a 2015 "re-review" of Eskridge's 1996 book: "A prophet before his time, William Eskridge has the satisfaction of having finally been vindicated." At the same time he was working on marriage rights for LGBT persons, Eskridge was working with Georgetown law professor Nan Hunter on teaching materials for a field they dubbed "Sexuality, Gender, and the Law". Eskridge and Hunter rejected the idea that the field should be defined as "Sexual Orientation and the Law", because they considered norms of gender and sexuality inextricably intertwined. Published by Foundation Press,
Sexuality, Gender, and the Law is in its fifth edition . Emerging from his work with Hunter, Eskridge published a series of articles on sodomy laws and other discriminatory laws harming gender and sexual minorities. An
amicus brief he wrote for the
Cato Institute and a law review article titled "Hardwick and Historiography". were cited by the majority opinion in
Lawrence v. Texas (2003), where the Supreme Court invalidated consensual sodomy laws. ==Consumer law==