In the 1980s, conservatives and feminists joined to fight a common nemesis: the spread of pornography. Unlike past campaigns to stamp out smut, this one was based not only on morality but also public safety. They argued that hard-core erotica was intolerable because it promoted sexual violence against women. "Pornography is the theory; rape is the practice," wrote feminist author Robin Morgan. In 1986, a federal commission concurred. Some kinds of pornography, it concluded, are bound to lead to "increased sexual violence." Indianapolis passed a law allowing women to sue producers for sexual assaults caused by material depicting women in...