LSU law professor John Baker has recently published a report documenting the continued expansion of federal criminal law for the Heritage Foundation. As Baker points out, there are now some 4500 different federal crimes, with the number growing consistently at a rate of about 50 new federal crimes every year for the last several decades. This expansion has continued apace under both Republican and Democratic-controlled congresses.
Why should we care about the growth of federal criminal law? After all, does it really make a difference whether a defendant gets hauled into federal court or state court? It does for at least three reasons.
First, federalization imposes the same rule on all fifty states. It thereby undermines the advantages of competition and diversity that flow from decentralized federalism... It also prevents states from competing with each other by offering different legal regimes and allowing individuals and businesses to choose the one that suits them best by "voting with their feet." John McGinnis and I discuss the competition and diversity rationales for decentralization in greater detail in this article.
Second, federal sentences tend to be stiffer than state ones, and federal court procedural rules more pro-government. As a result, getting hauled into federal court instead of state court makes it more likely that the defendant will be convicted, and more likely that he will get a lengthy sentence (though, in fairness, incarceration in a federal prison tends to be safer than life in state prisons, because federal prisons contain very few rapists and murderers). Interestingly, Baker points out that many of the new federal crimes don't have a "mens rea" requirement. In plain English, that means that a defendant can be convicted even if he didn't know that he was committing a criminal act and didn't intend to do so.
Third, the expansion of federal criminal further undermines the constitutional principle that the federal government is one of limited and enumerated powers. If the feds can criminalize virtually any activity they disapprove of, there is little in the way of effective structural limits on federal government power.
This is not to say that expansion of federal criminal law is never justified. For example, the feds may have a legitimate role to play in combatting crimes that threaten national security. However, there is no good rationale for the massive of expansion of federal jurisdiction over activities such as medical marijuana use that have few or no interstate effects.
Unfortunately, the Supreme Court has licensed virtually unlimited expansion of federal criminal law in cases such as Gonzalez v. Raich, where the Court held that Congress can use its powers to regulate "regulate commerce. . . among the several States" to criminalize almost anything.
Hopefully, Congress and the Court will rethink their approach to these issues, though I'm not optimistic that either will do so anytime soon.