The U.S. Supreme Court on Tuesday hears about a love triangle, complete with attempted poisonings and 24-hour surveillance by postal inspectors. Although it sounds like an episode of Law & Order (with a dash of Days of Our Lives), the case has global implications.

In 2005, Carol Anne Bond was a 34-year-old Philadelphia suburbanite living with her husband of 14 years. But when she found out that her best friend was pregnant and that her own husband was the father, she became enraged and began threatening her friend, by phone and in writing.

Bond pleaded guilty to harassment charges in state court, but was not deterred. She quickly moved on to more dangerous conduct. Over the next eight months, Bond stole toxic chemicals from the chemical manufacturing company where she worked and ordered other chemicals over the Internet. She combined the chemicals into a compound that is potentially lethal in small amounts — and is also bright orange. Bond spread the toxic material on her rival's mail, mailbox, front doorknob, car door and other surfaces.

But because of the orange color, the mistress, Myrlinda Haynes, easily spotted the chemicals and avoided any injury except a thumb burn.

Haynes complained more than a dozen times to the local police, who refused to take any action. Eventually, her mail carrier alerted the Postal Service, which videotaped the betrayed wife spreading the chemicals 24 separate times.

So What Does All This Have To Do With A Treaty?

The federal government prosecuted Bond for violating the Chemical Weapons Convention, a treaty signed by the United States that bans the unauthorized use or storage of dangerous chemicals. Bond was convicted and sentenced to six years in prison — three times the sentence she could have received if the state had chosen to prosecute her.

She appealed to the Supreme Court, contending that the statute Congress passed to enforce the treaty is unconstitutional because it violates states' rights.

Former Solicitor General Paul Clement, who represents Bond, contends that a simple assault case like this is the state's business to prosecute if it wishes to do so, not the federal government's. The treaty power, he argues, cannot trump the Constitution's structure of limited federal power.

"Is it really necessary to criminalize an individual's conduct" in a situation like this, he asks, "when it doesn't involve multiple victims or acts of terrorism?"

The answer, Clement will tell the Supreme Court, is "no."

The government counters that the treaty power does indeed pre-empt states' rights and always has. John Bellinger, who served as legal adviser for the State Department in the George W. Bush administration, notes that "one of the key purposes of the Constitution" was to give the federal government power not only to enter into treaties, but also to compel the states to comply with those treaties.

Bellinger has filed a brief in the Bond case, signed by legal advisers who served in administrations Democratic and Republican dating back to the 1960s.

He points out that one of the reasons the Founding Fathers wrote the Constitution to replace the Articles of Confederation was that the earlier document allowed the national government to enter into treaties, but not to compel the states to comply. That made other countries reluctant to make agreements with the U.S.

The Constitution changed that, says Bellinger, and as far back as the presidency of George Washington and the first Congress, the United States has negotiated treaties that trump state laws on all manner of subjects.

But Clement disagrees, saying the countries that negotiated and signed the Chemical Weapons Convention were not worried about crimes like Bond's. "Nation-states conduct war," he observes. "They don't poison their husband's lover."

Is It 'Peaceful' To Poison Your Husband's Lover?

Clement contends that Bond's actions were "peaceful," and therefore exempted from the treaty, because of the definition of "peaceful" in international law. Treaties, Clement says, "distinguish peaceful as basically being non-warlike." Bond's run-of-the-mill assault, he argues, did not implicate national and international concerns the way a terrorist attack would.

The government forcefully disputes Clement's interpretation, noting that the first ban on chemical weapons in 1920 banned only instruments of war, whereas the 2003 convention was specifically enacted to ban the storage or use of chemical weapons for a variety purposes.

"If Mrs. Bond's actions had ended up killing the victim, or killing a postal worker, or killing the victim's child, I don't think anybody would dispute that this was an appropriate use of this convention," contends Bellinger, the former State Department legal adviser.

Clement, however, holds firm and poses his own hypothetical. "I think you could tell 100 people on the street what Ms. Bond did here," he says, and none of those people would determine that Bond "deployed a chemical weapon."

This is the second trip to the Supreme Court for Bond. In 2011, the court dodged this issue, sending the case back to the lower courts. But this time, Bond and her lawyers are directly challenging the court's most famous treaty decision, written in 1920 by Justice Oliver Wendell Holmes. That decision said that "if the treaty is valid there can be no dispute about the validity of the statute" intended to implement it.

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