Abstract: American capital practice has changed markedly over the past four decades. Constitutional regulation of state death penalty practices has transformed the size and scope of capital trials; federal and state court review of capital verdicts has become more intricate and time-consuming; and state death rows remain quite large despite significant declines in capital sentencing. These changes have altered the cost of capital punishment and, perhaps more importantly, public perceptions about the cost of capital punishment. Government officials, death penalty opponents and supporters, and the broader public have slowly but now almost unanimously concluded that the costs of capital punishment outweigh the costs of lifetime noncapital incarceration. This article documents the emergence of the cost argument against the death penalty and discusses the rhetorical and strategic functions of such an argument in the modern era, including the possible role of cost in bringing an end to the American death penalty.