Carol Anne Bond tried to poison her husband’s girlfriend. Nothing wrong with that, right? Or at least nothing wrong as a matter of federal law, which ordinarily doesn’t concern itself with private assaults that take place in a single state.

Federal prosecutors in Pennsylvania thought otherwise. They charged her with violating the 1998 Chemical Weapons Convention Implementation Act, passed by Congress in fulfillment of U.S. obligations under the treaty known as the Chemical Weapons Convention -- you know, the one that makes it illegal for dictators to gas civilians. Bond got six years -- and now the U.S. Supreme Court must decide if the law properly applied to her.

As a matter of the prosecutors’ discretion, the decision to charge Bond under the law is outrageous. She had spread potassium dichromate and an arsenic-based chemical on doorknobs and door handles that her rival was likely to touch, and she managed to give her victim a rash on one thumb. Local law covered it -- and anyway, it cheapens a law passed by Congress in fulfillment of our international treaty obligations to apply it to petty disputes.

But as often happens by the time you get to the Supreme Court, an important legal principle came into play that no one anticipated when the case got started. The principle here can be stated simply: Does Congress have an independent power to enact laws derived from binding treaties signed by the president and approved by the Senate?

War Tribute

This question has a fascinating history that is almost a century long. The Supreme Court first addressed it in 1920, in Missouri v. Holland, a landmark opinion by Justice Oliver Wendell Holmes Jr. The U.S. had signed an early environmental treaty with Canada that regulated hunting of migratory birds, and Congress had passed an implementing law. At the time, Congress’s power to regulate interstate commerce was still interpreted pretty strictly, and no court had held that Congress could lawfully regulate birds flying between the states because of its effects on interstate commerce.

Holmes, writing for the court, held that Congress had an independent power to make law, outside the commerce clause of the U.S. Constitution, because there must be some way to make the treaty apply domestically. “It is not lightly to be assumed,” he wrote with characteristic brio, “that, in matters requiring national action, ‘a power which must belong to and somewhere reside in every civilized government’ is not to be found.” It would be ridiculous, in other words, if the U.S. could make treaties but couldn’t enforce them. If federalism blocked treaty making, the U.S. would be a banana republic.

Holmes acknowledged that it was hard to find this independent power in the text of the Constitution -- but he didn’t care. The founders, he wrote, “called into life a being the development of which could not have been foreseen completely by the most gifted of its begetters.” Originalism was bunk. What was more, Holmes had fought, was injured and lost his closest friend in the Civil War, a conflict that he believed had changed the constitutional structure of the country. “It has taken a century and has cost their successors much sweat and blood to prove that they created a nation,” he wrote. The modern federal government was a tribute to the Civil War dead.

If that gives you shivers, it was supposed to. Yet the issue of congressional power to make law pursuant to treaties wasn’t closed. In 1957, in a case called Reid v. Covert, the court considered the cases of two military wives who killed their husbands abroad, one in Japan and one in England. Each of them was tried by court-martial pursuant to treaties the U.S. had with the host countries; unsurprisingly, the all-male military juries convicted them.

Rights Infringed

This time, the Supreme Court, with Justice Hugo Black writing a plurality opinion joined by three of his colleagues, said that the women’s right to due process and trial by jury had been unconstitutionally infringed by trying them in a court-martial. The treaty made no difference, he wrote, because Holmes’s opinion in Missouri v. Holland only applied when it was a matter of giving Congress a power that would otherwise be reserved for the states.

Black’s plurality opinion tells you how the poisoning case should come out. None of Carol Anne Bond’s fundamental constitutional rights were violated. She got due process and a trial before her peers. And Holmes was right that a civilized country has to be able to pass laws that make its treaties into more than empty promises.

But there’s also an important lesson here about prosecutors gone wild. In the shadow of the massacre of Syrian civilians using chemical weapons, the Barack Obama administration must be very unhappy to find itself in court defending its right to pass laws under the Chemical Weapons Convention. Valuable government resources are being spent to defend a constitutional principle whose logic has been clear for 50 years. All this is happening because federal prosecutors in Pennsylvania wanted to do something cool and use a federal statute to reach crimes of the kind to which they had not been previously applied.

As Holmes said, federal law is not some free gift. It was hard won by sweat and blood. No one should disrespect it -- especially those charged with its enforcement.

(Noah Feldman, a law professor at Harvard University and the author of “Cool War: The Future of Global Competition,” is a Bloomberg View columnist. Follow him on Twitter at @NoahRFeldman.)

To contact the writer of this article: Noah Feldman at noah_feldman@harvard.edu.

To contact the editor responsible for this article: Tobin Harshaw at tharshaw@bloomberg.net.