A big constitutional law battle is about to reach its climax – a battle between the Supremacy Clause of the Constitution and the Tenth Amendment. The Supremacy Clause (Article VI, Clause 2) states, “This Constitution, and the Laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land.” The Tenth Amendment reads, “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.”

The Tenth Amendment was intended to assure ratifying States that the powers of the federal government were limited and would not displace powers and areas of law traditionally belonging to the States. However, with an ever-expanding federal government, there have been increasing clashes of federal and state law. For example, real property and land use laws traditionally are within the bailiwick of the States. However, state control of this area is increasing displaced by federal environmental laws and regulations through the process of preemption.

Preemption has its roots in the Supremacy clause and has been interpreted to mean where the federal and state governments are attempting to regulate the same conduct, state law will be given deference unless Congress has demonstrated a clear and manifest purpose to displace state law.

The place of treaties in the Supremacy Clause has been open to debate. Are they at the same level as the Constitution? Are they separate and apart from the Constitution? If they are, could the United States, under treaty law, be required to perform an unconstitutional act? For example, the Second Amendment recognizes the citizens’ right to bear arms. Nevertheless, this September, Secretary of State John Kerry signed the UN Arms Trade Treaty, which seeks to control the international transfer of firearms, parts and ammunition.

Soon, we may receive some enlightenment in this muddy area. This week, the Supreme Court heard arguments in Bond v. U.S., a case involving Pennsylvania resident Carol Bond, who spread a toxic chemical on the car and mailbox of a friend who had an affair with her husband. The chemical did minimal harm despite her clear intent to do so. This should have been a problem handled by Pennsylvania law, but the Feds charged Bond with violating the chemical-weapons convention that the Senate ratified in 1997. Unbelievably, she was convicted of waging chemical warfare. (Too bad Vladimir Putin didn’t intervene to protect Bond as he did Syria’s Bashar al-Assad.)

This is Bond’s second trip to see the Supremes. Two years ago, they ruled 9-0 that Bond could challenge her conviction under the Tenth Amendment. However, on remand, the lower courts still upheld her conviction.

Limited federal powers were of paramount importance to the Framers of the Constitution. Before ratification of the Constitution, each State was considered a separate state, a nation under international law, joined in a confederation. They jealously guarded these rights by limiting the powers of the new federal government while retaining those powers not ceded to the federal government to themselves through the Tenth Amendment. The Framers surely didn’t intend that treaties would be used to end-run constitutional restraints under guise of the Supremacy Clause. Yet Bond may have an upstream fight. Among those filing friend of the court briefs in favor of the government’s position are Professors of International Law and Legal History and Former State Department Legal Advisers. Let’s hope the view of the Framers is upheld by the Supreme Court.