Say you rush into a busy airport and are late for a flight that you cannot miss. Maybe your bag has a hole in it, stuff is falling out, it’s bedlam. You get to the check-in counter and the customer service agent says “flight’s cancelled.”

You’re upset. Maybe the agent snickers at you and says he’s too busy to help you rebook a flight even though it’s obvious he’s not. You ask for the clerk’s name and say that you want to report him, but he refuses to give it to you.

Now, your blood is boiling and, foolishly, you reach out and grab the agent’s identification badge, perhaps jostling the clerk in the process. Now you’ve crossed the line!

In fact, you’ve committed the crime of assault (and quite possibly the additional crime of battery), which is a crime in all fifty states, which could result in a jail sentence of six months to a year (more, if you actually touch the person and serious injury results).

If a union gets its way, what is already a crime in all fifty states would also become a federal crime that could result in ten years in federal prison. At the behest of the International Association of Machinists and Aerospace Workers (writing here and here), Sen. Maria Cantwell, D-Wash., has offered an amendment hidden deep within a Federal Aviation Administration reauthorization package.

The amendment to 49 U.S.C. § 46503 would make it a federal crime to assault (a threat of bodily harm with an apparent, present ability to cause the harm) any “air carrier customer representative in an airport, including a gate or ticket agent, who is performing the duties of the representative or agent,” punishable by “not more than 10 years” in prison.

While nobody condones assaulting an airline customer service agent, is there any reason why this needs to be a federal crime when it is already a crime in all 50 states?

Why single out airline customer service agents in this way? After all, airports are not federal property, and regular airline employees (gate agents, ticket agents, baggage handlers) are not federal employees.

Unlike TSA agents, who are federal employees, these employees don’t perform any “security” function inside the airports. This appears to be a classic example of overcriminalization: the overuse and misuse of criminal law.

There are other problems with this amendment too. First, it is entirely unclear that Congress has the authority to enact this amendment. Under the Constitution, Congress is granted only certain enumerated powers and policing scraps between private parties on non-federal property is not among them.

The general police power rests with the states. Moreover, assault against federal employees or on federal property is a federal crime many times over (consider 18 U.S.C. §§ 111, 113, 115, 351, 1501, and 49 U.S.C. § 46504).

Second, the bill imposes a criminal penalty that appears disproportionate to the offense. Simple assaults covered by the bill, like making a threatening gesture, do not require any bodily contact or injury.

Under existing federal law, if you make such a menacing gesture to a federal judge, a federal law enforcement officer, or a Member of Congress, you could go to jail for a year (more if you actually make physical contact or cause bodily injury). But if you do that to an airline ticket agent, under this amendment, you could go to federal prison for ten years.

Ramping up relatively minor violations of state law into major federal felony offenses is no small or abstract problem. Just ask John Yates.

For throwing some undersized fish overboard to avoid a citation, the fisherman was convicted of violating the so-called anti-shredding provision of the Sarbanes-Oxley Act of 2002: A federal law that punishes evidence destruction to impede federal investigations with up to 20 years in prison. His conviction was ultimately overturned by a closely-divided Supreme Court.

During oral argument in the case, the late Justice Antonin Scalia asked, “What kind of a sensible prosecution is that?” After the government’s attorney responded that prosecutors are selective and don’t try to convict everyone who throws fish overboard, Chief Justice John Roberts replied :

“But the point is that you could, and the point is that once you can, every time you get somebody who is throwing fish overboard, you can go to him and say: Look, if we prosecute you you’re facing 20 years, so why don’t you plead to a year, or something like that. It’s an extraordinary leverage that the broadest interpretation of this statute would give Federal prosecutors.”

One question for Congress is should the same “extraordinary leverage” arise for simple assault of private airline ticket agents? With all due respect to airline customer service agents, this amendment appears to be a solution in search of a problem and exemplifies the ills of overcriminalization.