The Volokh Conspiracy

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Criminal Law

Legal Conventions and Criminal Law

Substantive criminal law consists of more than statutes and formal common law.


Thank you to the Volokh Conspiracy for allowing me to guest blog this week about my article The Modern Common Law of Crime.

Let me start off with a question: Can the Queen of England, against the wishes of her government, veto a bill that passes both houses of parliament? To pose the question immediately invites a charge of equivocation. What do I mean by "can"?

As a matter of formal law, she could. No governmental official has the legal power to force the Queen to sign a bill that passes parliament. If she decided to withhold the royal assent from a bill, that bill would not be law, and no British court or other legal institution would recognize it as such.

But, of course, the Queen cannot actually veto a bill against the wishes of her government. Her veto would create a constitutional crisis that would imperil the monarchy. The Queen knows this, and she recognizes that the act would widely be viewed as illegitimate and unconstitutional. As a result, despite what formal law allows, the Queen lacks the effective power to refuse the royal assent on legislation that passes parliament.

The requirement that the Queen sign a bill is a type of legal convention. A "convention" is a kind of rule that is (1) not statutory or written law; (2) nor unwritten law enforceable within the courts or other legal institutions (i.e., it is not common law); but (3) is generally accepted as binding on legal actors; and (4) is enforceable against legal actors through indirect methods such as political pressure. Conventions are not merely exercises of discretion. As Adrian Vermeule explains in his article Conventions in Court, a legal convention must "rest[] on a sense of normative obligation." The Queen provides the royal assent to all bills because that is her duty under the British constitution, not because she thinks withholding her assent would be a bad idea.

British constitutional conventions may be the easiest and most visible legal conventions. But legal conventions exist throughout the American legal system, too. For example, by convention (and sometimes by state law), Presidential electors must vote for the candidates for whom they pledged and, before the adoption of the Twenty-Second Amendment, convention had limited the president to two terms in office. Adrian Vermeule, Keith Whittington, and others have written about these conventions, especially as they affect the organization of the federal government and other constitutional arrangements.

Today, two accounts are generally given of modern American criminal law. The first—the one often told by judges—is that criminal law is statutory and legislatures are supreme. Federal common law crimes do not exist, and state common law crimes have largely been abolished. Judges frequently proclaim in strong language that the definitions of crimes rest wholly with the legislature. The second—the one often told by academics—is that prosecutors determine the criminal law. This story, like the first, begins with legislative supremacy, but it ends with democratic dysfunction and delegation of power. Legislatures exercise their power over criminal law by passing broad, vague, and overlapping laws. They do a poor job of repealing ineffective and obsolete laws. Federal crimes largely duplicate state crimes. Virtually everyone commits some offense, nearly every day. Because criminal law is broader than any prosecutor could enforce, legislatures have, in practice, delegated prosecutors with near-plenary power over the criminal justice system.

In my paper The Modern Common Law of Crime, I provide a third account, arguing that American criminal law has become heavily a conventional law. That is, much of our criminal law consists of unwritten common-law-like norms that are widely acknowledged and generally respected but lack the status of formal law recognized by the legal system. These conventions act as a necessary supplement to statutory criminal law.

For example, as a matter of formal statutory law, Wisconsin declares adultery to be a felony, federal law punishes off-duty law enforcement officers who bring firearms within 1,000 feet of a school with up to five years in prison, and speed limits on many interstates are 55 miles per hour. But that is not the real law, and everyone knows it. Adultery is not prosecuted in Wisconsin, federal prosecutors do not indict off-duty police officers for carrying their weapons, and the true speed limit on most roads is about 10 to 15 miles per hour over the posted limit.

These conventions are followed from a sense of obligation and with recognition that some form of non-legal sanction may result if they are not followed. Just like, for example, the Queen cannot (really) veto a bill, Wisconsin district attorneys cannot really prosecute adultery because of the non-legal sanctions they would face if they tried, regardless of their personal beliefs about whether adultery should be criminalized.

Over the next week, I will discuss criminal law conventions in more depth. The topics will include a more detailed account of the existence and characteristics of criminal law conventions, a defense of their legitimacy, a descriptive account of the institutional arrangements that produce them, and a discussion of how legislatures and courts should respond to a criminal law that consists heavily of norms that rely primarily on nonlegal sanctions for their enforcement.