Civics class teaches the traditional mode of law enforcement: The legislature adopts a regulatory statute, and the executive enforces it in the courts. But in an increasingly interconnected world, a nontraditional form of regulatory litigation is possible in which public enforcers from one government enforce laws adopted by a second government in the second government’s courts. That is, one government provides the executive while the second provides the legislature and the judiciary. I call this nontraditional form “diagonal public enforcement.”

Although diagonal public enforcement has escaped systematic study, one can find examples in U.S. courts going back more than a century. Foreign governments have used U.S. courts to enforce federal antitrust laws, state environmental laws, and civil rights statutes, among others. Recently, the U.S. Supreme Court heard a case in which the European Community sued U.S. tobacco companies in a federal court in New York under the Racketeer Influenced and Corrupt Organizations Act. Diagonal public enforcement occurs within the U.S. system as well. States routinely enforce federal laws in federal courts, and opportunities exist for states to enforce sister-state law, especially with respect to climate change and other cross-border issues.

Despite these examples, some view diagonal public enforcement as a category error: Why would legislatures rely on foreign governments to enforce domestic law, and why would foreign executives take up the task? In light of these questions, this Article attempts to demystify diagonal public enforcement by exploring when it is consistent with the rational pursuit of legislative and executive interests. Legislatures are likely to authorize diagonal public enforcement in order to increase deterrence or influence global regulation. Executives are likely to forum shop for diagonal options in order to achieve better outcomes in foreign courts. These predictions explain existing patterns of enforcement and suggest a larger role for diagonal public enforcement in the coming years.

Finally, this Article critically evaluates the costs and benefits of diagonal public enforcement at the interstate, intrastate, and individual levels. At first glance, diagonal public enforcement may seem to raise concerns about the diffusion of regulatory authority, the extraterritorial reach of domestic law, and the interference in relationships with foreign sovereigns. Upon closer scrutiny, however, diagonal public enforcement turns out to have the capacity to improve enforcement efficacy, promote the public interest, protect foreign and minority interests, and nudge gridlocked institutions. At least under certain conditions, therefore, these transgovernmental cases may be models for deeper cooperation and improved enforcement.

* Assistant Professor of Law, Cornell Law School.