Most bodies of substantive law define citizens' obligations. Criminal law is different. Its primary role is not to define obligations, but to create a menu of options for prosecutors. If the menu is long enough - and it usually is - prosecutors can dictate the terms of plea bargains. When that is so, litigants in criminal cases do not bargain in the shadow of the law. Rather, they bargain in the shadow of prosecutors' preferences, budget constraints, and political trends. Law's shadow disappears.This points to a basic irony about criminal law: the more it expands, the less it matters. In other areas, the size of law's empire varies roughly with law's scope. Criminal law is different. The greater the territory substantive criminal law covers, the smaller the role that law plays in allocating criminal punishment.
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