Page 10 of 42 103 Minn. L. Rev. 844, *861 When resource constraints remain, however, they force officials to choose which cases get priority. That creates more opportunity for biases and favoritism to play a role in determining which cases to charge and which to forgo. That is especially so with crimes in which evidence development is more costly, so officials have to decide whether to invest scarce resources in those that require substantial investigative efforts. Both sexual assault and police violence cases often require larger-scale investments to develop evidence sufficient for prosecution. Failures to make those investments are common reasons for non- prosecution in both contexts. >? Il. MECHANISMS OF PROSECUTORIAL ACCOUNTABILITY For a range of reasons and across a range of contexts, public prosecutors’ failures to enforce criminal law have been of sufficient concern to lead contemporary justice systems to devise checks against unjustified underenforcement. Approaches take three basic forms: (1) limited authority for private parties to initiate or participate in criminal prosecutions; (2) independent review of initial non-prosecution decisions, upon petition from a [*862] victim; and (3) multiple, mdependent public prosecution agencies with independent authority to bring charges for the same wrongdoing. Outside the United States, the first two options predominate; their expansion in recent years is a direct consequence of broader reforms to expand crime victims' rights. © U.S. jurisdictions, however, rely almost wholly on the third model. Despite having adopted otherwise expansive victims’ rights laws in recent decades in response to an influential movement for crime victims' rights, state and federal laws consistently and explicitly avoid granting any formal authority to private parties, or courts, over criminal charging. The next three Sections provide an overview of these options, where they exist. Largely with regard to U.S. policy choices only, they also