This term the Supreme Court will rule on important subjects from racial preferences to restrictions on political speech, but its most momentous case, to be argued Tuesday, concerns the prosecution of a Pennsylvania woman who caused a chemical burn on a romantic rival’s thumb. The issue is: Can Congress’ powers, which supposedly are limited because they are enumerated, be indefinitely enlarged into a sweeping police power by the process of implementing a treaty?

Carol Bond, an immigrant from Barbados, who worked for a chemical manufacturer, is contesting a six-year prison sentence imposed because, when she discovered that her best friend was pregnant from an affair with Bond’s husband, she became distraught, perhaps deranged, and contaminated her friend’s car and mailbox with toxic chemicals. Federal prosecutors, who seem prone to excess, turned this local crime into a federal offense – a violation of legislation Congress passed to implement the 1993 Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction.

Bond pleaded guilty to causing the thumb burn (which was treated by rinsing it with water) but retained the right to appeal on 10th Amendment grounds. That amendment, which the Supreme Court has called the “mirror image” of the Constitution’s enumerated powers structure, says: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people.”

Two years ago, Bond argued in the Supreme Court that she had the right to object that her offense was not properly within federal jurisdiction. She won, the court ruling unanimously that an individual, not just a state, can raise 10th Amendment claims. Justice Anthony Kennedy wrote for the court that federalism does not merely set boundaries between governmental institutions for their own benefit, but also “protects the liberty of all persons within a state by ensuring that laws enacted in excess of delegated governmental power cannot direct or control their actions.”

Bond’s case was remanded to a lower court, which considered her argument that Congress cannot broaden its powers using legislation that implements a treaty. She lost there. But a judge, although concurring in the ruling against her, called her case “a troublesome example of the federal government’s appetite for criminal lawmaking” (the federal criminal code includes more than 4,450 crimes). He hoped the Supreme Court would “clarify (indeed curtail) the contours of federal power” to intrude on local matters.

Bond’s brief for Tuesday argues that the power to ratify treaties neither confers upon Congress a general police power nor guarantees the validity of implementing legislation: “The absence of a national police power is a critical element of the Constitution’s liberty-preserving federalism.”

The government says that only the prohibitions of the Constitution’s first eight amendments limit the government’s powers when implementing a treaty; otherwise, it is unfettered. Bond, however, has Alexander Hamilton on her side: In Federalist 84, he said that the entire Constitution, by its federal structure, “is itself, in every rational sense, and to every useful purpose, A BILL OF RIGHTS.”

As Kennedy wrote in an earlier case, it is mistaken to believe “that the only, or even the principal, constraints on the exercise of congressional power are the Constitution’s express prohibitions.” The Constitution’s “structural provisions” are not, Bond’s brief argues, “second-class citizens” among the document’s “liberty-protecting provisions.”

In a 1920 case, Justice Oliver Wendell Holmes, whose deference to Congress often was dereliction of the judicial duty to stymie legislative excesses, said that if a treaty is valid, what Congress does to implement it is “necessary and proper.” A paper by the libertarian Cato Institute responds:

“If Holmes was correct, the treaty power can be used to undo the carefully wrought edifice of a limited government assigned only certain enumerated powers. That those who drafted and ratified the Constitution intended to bury such a dormant time bomb in their handiwork is too much of a stretch to be seriously entertained.”

No one argues that Bond intended to kill with the bright orange chemical her victim easily detected. And the federal government did not intervene in the Bond case because her action threatened a distinctly federal interest. It intervened because it thought it could: Government’s will to power is an irresistible force until it meets an immoveable object – a court. Which is why our Constitution requires not judicial deference but active judicial engagement in defense of its liberty-protecting structure. And why the case of the mildly injured thumb matters so much.

© 2013, Washington Post Writers Group