The rapid expansion of federal criminal law, beyond almost all prudential and constitutional limits, may not be the first thing to leap to mind when one thinks of key problems with American criminal law. But the existence now of over 4,450 federal criminal offenses is itself a problem that implicates the foundations of the criminal law. The number of federal offenses is too great for Ameri­cans to be familiar with all of the conduct that is criminal, and many of the offenses themselves are deeply flawed, omitting essential substantive elements necessary to pro­tect the innocent. As a result of these flaws, the federal criminal code fails to serve what may be its most impor­tant function, which is not to expose and punish the relatively few persons who consciously choose to engage in criminal conduct, but to inform citizens of the law's requirements, thereby equipping them to avoid the con­duct deemed worthy of society's most severe penalty and moral censure.

The explosion of the federal criminal law—both in the number of offenses and their overall scope—demands that legal reformers revisit basic assumptions about what crimi­nal law is and how best to rein in its actual and potential abuses. Over the last forty to fifty years, government at all levels has succeeded in convincing Americans that the criminal law is whatever legislators define it to be. Ill­ conceived new criminal offenses occasionally raise an eye­brow or two, but Americans generally accept their legitimacy. The result is that Americans have come to rely, consciously or not, on the good graces of prosecutors and the laws of probability to shield them from prosecution. When lightning does strike and an otherwise law-abiding citizen is charged and convicted for conduct that is not traditionally criminal or necessarily even wrongful, most Americans convince them­selves that the accused must have done something to warrant the prosecutor's attention. Yet while Americans remain incredulous that improper criminal laws could be used to convict someone who had no intention of doing anything wrongful, the reality is otherwise.

I. Substantive Protections

"An unjust law is a code that is out of harmony with the moral law," wrote Martin Luther King, Jr., who had no lit­tle experience with unjust law. Many federal criminal offenses fall far short of this standard because they do not require an inherently wrongful act, or even an act that is extraordinarily dangerous. In the days when average citi­zens were illiterate, they could still know and abide by the criminal law. At that point, most criminal offenses addressed conduct that was inherently wrongful­—malum in se—such as murder, rape, and robbery. That is no longer the case. Most of today's federal offenses crimi­nalize conduct that is wrong only because it is prohibited—malum prohibitum.

Worse, many of these prohibitions are actually contrary to reason and experience, giving average Americans little notice of the content of the law. For example, few would imagine that it is a federal crime for a person to violate the terms of service of an online social networking site by reg­istering with a fake name, as a recent federal indictment in Los Angeles alleges. Indeed, many Americans might instead expect this behavior to be protected, for it pro­motes privacy and anonymity and, by extension, the personal safety of vulnerable users. Another example: Unauthorized use of the 4-H organizations logo is a fed­eral crime. There are undoubtedly reasons that these laws are on the books, but they are not reasons that average law-abiding Americans would be likely to anticipate when trying to conform their conduct to the law's requirements.

Exacerbating the criminalization of an ever-increasing array of behavior that is not inherently wrongful is the crumbling of traditional protections in the law for those lacking wrongful intent. Historically, a criminal conviction required that a person both

committed an inherently wrongful act that consti­tuted a serious threat to public order, and did so with a guilty mind or criminal intent, that is, mens rea.

These two substantive components were essential for con­viction in almost all criminal cases from the time of the American founding through the first decades of the 20th century.

But over the past few decades in particular, Congress has routinely enacted criminal laws that lack mens rea requirements or that include mens rea requirements that are so watered down as to provide little or no protection to the innocent. As a result, honest men and women increas­ingly find themselves facing criminal convictions and prison time. This happens even when their "crimes" are inadvertent violations that occur in the course of otherwise lawful, and even beneficial, conduct.

Despite increasing attention to this problem in recent years, the trend is for fewer and weaker mens rea require­ments. In a recent study, Professor John Baker found that seventeen of the ninety-one federal criminal offenses enacted between 2000 and 2007 lacked any mens rea requirement whatsoever. The Heritage Foun­dation and the National Association of Criminal Defense Lawyers will soon publish the results of their joint research into the mens rea provisions in bills introduced in the 109th Congress. Preliminary findings reveal that the majority of those offenses lack a mens rea require­ment sufficient to protect from federal conviction anyone who engaged in the specified conduct but did so without criminal intent.

Many lawyers seem to accept uncritically the idea that any act made criminal by a legislature is, by that fact alone, an actus reus. But to accept that definition is to obliterate the meaning of actus reus, for the term would be a mere synonym for "act that has been made criminal." The prob­lem may be best illustrated using some of the "criminal" laws made and enforced by totalitarian regimes. For exam­ple, in some communist countries it was deemed a "criminal" act for relatives of politically or religiously perse­cuted persons to discuss their relative's persecution, even in private and even with other family members. In some regimes, any type of unauthorized communication with a foreigner was deemed a "crime." Regardless of any elabo­rate (or convoluted) logic and rhetoric that may be used to justify criminalizing such conduct, it is evident that there is no actus reus in these so-called crimes.

Similarly, but to a lesser extreme, when Congress makes it a federal crime to violate any foreign nation's laws or regulations governing fish and wildlife—as it has done in the Lacey Act—many violations will be "crimes" that include no actus reus. Some of those foreign regula­tions may do nothing more than protect the foreign nation's local business interests. For example, the fishing regulations of a small Central American nation might require fishermen to package their catch in cardboard, perhaps only in order to stimulate business for a domestic cardboard manufacturer. If a fisherman then packs his catch taken in that nation's waters in plastic rather than cardboard and imports into the United States—in viola­tion of the express terms of no federal or state law of the United States—is there a real actus reus? Answering yes leads to the absurd conclusion that Congress could, with a single sentence in a single legislative act, make it a crime to violate any and every law of every nation on earth—and that every such offense thereby includes a meaningful actus reus. Such may be positive law, but they are not "crimes" in the truest sense of the word; they are merely legislatively created offenses that are unworthy of any free nation's criminal law.

The size of the federal criminal law compounds these problems and undermines other protections. The Princi­ple of Legality, for example, holds that "conduct is not criminal unless forbidden by law [that] gives advance warning that such conduct is criminal." The sheer num­ber and disorganization of federal criminal statutes ensures that no one could ever know all of the conduct that has been criminalized. Those who have tried merely to count all federal offenses—including both Professor Baker and the Justice Department itself—have been able to provide only good estimates. The task proves impossi­ble because offenses are scattered throughout the tens of thousands of pages of the United States Code (not to men­tion the nearly 150,000 pages of the Code of Federal Regulations). If criminal-law experts and the Justice Department itself cannot even count them, average Amer­icans have no chance of knowing what they must do to avoid violating federal criminal law.

II. The Threat to Liberty

The power to punish criminally—including the depriva­tion of one's personal liberty and even one's life—is the greatest power that government regularly exercises with respect to its own citizens. As Professor Herbert Wechsler famously characterized it, criminal law "governs the strongest force that we permit official agencies to bring to bear on individuals." Perhaps the central question that the Framers of the Constitution and the Bill of Rights debated, and to which they gave painstaking considera­tion, was how best to protect individuals from the unfettered power of government. They were well acquainted with abuses of the criminal law and criminal process and so endeavored to place in our founding docu­ments significant safeguards against unjust criminal prosecution, conviction, and punishment.

In fact, they understood so well the nature of crimi­nal law and the natural tendency of government to abuse it, that two centuries later, the most important procedural protections against unjust criminal punish­ment are derived directly or indirectly from the Constitution itself, specifically the Fourth, Fifth, Sixth, and Eighth Amendments.

But despite these protections, the wholesale expansion of federal criminal law—both as to the number of offenses and the subject matter they cover—is a major threat to Americans' civil liberties. Each time Congress crafts a criminal law covering a new subject matter, it effectively expands the power of the federal government. And the types of crimes that Congress now often creates—lacking a true actus reus or a meaningful mens rea requirement­—can effectively circumvent the Bill of Rights' procedural protections.

Of similar concern, criminal offenses that exceed the limits of Congress's limited, enumerated power are breaches of one of the primary structural limitations that constitutional federalism imposes on the federal govern­ment. After countenancing for decades Congress's almost unlimited criminalization of conduct that is inherently local in nature (as long as, that is, the Constitution's Com­merce Clause was invoked to justify the assertion of congressional authority) the Supreme Court rediscovered constitutional limits in United States v. Lopez and United States v. Morrison. In both of these cases, the Court explained that such limits on federal commerce power are consistent with and flow from the fact that Congress is a body of limited, enumerated powers.

The federal offense of carjacking is a quintessential example of Congress's overreaching assertions of federal criminal jurisdiction. The federal carjacking offense is cur­rently defined as taking a motor vehicle "from the person or presence of another by force and violence or by intimi­dation." The federal jurisdictional "hook" for this carjacking offense is that the vehicle must have been "transported, shipped, or received in interstate or foreign commerce," but how many vehicles have not? Actual com­missions of carjackings take place almost uniformly within a single locale of a single state, yet federal crimi­nal law now purports to authorize federal prosecutors to be the ones to charge and prosecute local carjackings. Such breaches of constitutional federalism are not mere breaches of technical and theoretical niceties, for the power to criminalize is the power to coerce and control. The purpose of constitutional federalism is akin to the purpose of limited government itself: to guard against accumulation of power by a single sovereign—i.e., the fed­eral government—as a "double security . . . on the rights of the people." Thus, if there were no limits on Con­gress's power to criminalize, there would be no limits on the power of the federal government to coerce and control Americans.

III. Prospects for Reform

The "overcriminalization" problem is so widespread and pervasive that it is tempting to think that reform is futile. But there is reason to hope that Congress may change its ways. The over-federalization of crime is not a partisan issue, and both major parties stand to benefit from fight­ing over-federalization once the public is better educated about the problem and its implications. With regard to the criminal law, Democrats generally recognize that the power to make laws and decisions about the enforcement of those laws should reside as closely as possible to those who will be most affected. Washington should in most cases not be dictating which members of the community should be locked up and for what conduct. Many Republi­cans tend to view constitutional federalism as a check on the unwarranted and potentially dangerous accumulation of power by a central government. Once they understand the mechanics and implications of the over-federalization of crime, Americans who support either party are likely to understand over-federalization as a grave threat to their rights and liberties.

Although most members of Congress remain prone to viewing their being "tough on crime" at the federal level as a hedge against unemployment, that tide is turning. Influ­ential Senators and Representatives of both parties are beginning to recognize the real-world effects of the over-­federalization of crime on individuals and communities in their home states and districts. Certainly nothing requires Congress to legislate to the full extent allowed by the Supreme Court's Commerce Clause jurisprudence. Some members of Congress thus have begun to work to change the political environment and block bills that would expand the reach of federal criminal law beyond prudential or constitutional limits. These leaders include Representatives John Conyers (D-MI), Louie Gohmert (R-TX), and Bobby Scott (D-VA) as well as Senators Jeff Sessions (R-AL) and Sam Brownback (R-KS). The projects of all those who advocate for the reform of federal criminal law would be advanced by reaching across real and per­ceived political boundaries to shape a coalition working to ensure that all new criminal offenses adhere to the funda­mental principles of sound criminal law.

In the long run, no one benefits when the federal government indiscriminately criminalizes conduct without regard to prudential and constitutional limitations. Perversely, overcriminalization undermines the rule of law over time, even as it chips away at liberty. Narrow special interests that pressure Congress to add criminal offenses that are not warranted by constitutional norms or prudence play a dangerous game with our freedoms. No one, Democrat, Republican, or otherwise, should countenance it.

Brian Walsh is a senior fellow at The Heritage Foundation.