This chapter examines the strategies and tactics of a major United States rights advocacy group, the American Civil Liberties Union (ACLU), in its campaign against a major piece of post-9/11 domestic security legislation introduced by the Bush administration – the USA Patriot Act. There is a substantial literature analyzing the work of interest groups devoted to human rights advocacy in both national and international contexts, much of which has focused on test-case litigation, the core activity of such groups domestically.1 The scholarly literature has given much less attention to legislative lobbying by human rights organizations, even though such groups typically are active in the legislative arena as well as in the courts. This study attempts in a modest way to redress that imbalance. By analyzing the ACLU’s congressional lobbying activities during a particularly challenging period for human rights advocates, it contributes empirically to an understanding of how rights organizations do their work.