Page 4 of 42 103 Minn. L. Rev. 844, *849 This Article has several aims. One is to introduce the concept of enforcement redundancy and demonstrate its utility. Another is to highlight problems of criminal law underenforcement and to situate contemporary complaints about failures to prosecute police violence and sexual assaults as specific examples of broader enforcement deficiencies that stem from bias and favoritism in police and prosecutorial discretion. The Article also defends the observation that enforcement redundancy strategies are responses to versions of this problem. It then assesses the strengths and weaknesses of different such strategies, with primary attention on the effectiveness of the U.S. approach of redundant federal-state authority. A focus on three different categories of criminal law underenforcement - government corruption, police violence, and sexual assaults - clarifies differences in the effectiveness of the U.S. approach. Federalism has proven an effective response to states’ failures to address forms of public corruption, and for those crimes, it is likely superior to its alternatives. Federal authority has had some success in compensating for states' failures to prosecute police violence and other police wrongdoing, but its efficacy is harder to judge and arguments for supplemental redundancy strategies are stronger. For sexual assaults, federal authority has failed to assert any meaningful enforcement jurisdiction to compensate for weaknesses in state justice systems. Despite the sustained efforts and notable successes of reform advocates in this area, no model of enforcement redundancy has made inroads. The Article proceeds as follows. Part II briefly surveys evidence of and reasons for underenforcement. The need for safeguards against unjustified nonenforcement has long been recognized in the United States and elsewhere; outside the United States, as part of victims’ rights reforms, it has been the object of institutional reforms. Part