Can the U.S. send domestic terrorists to international courts?

|The Volokh Conspiracy |

Does Article III of the Constitution allow the United States to create international tribunals to try American or foreign illegal combatants or terror suspects? Could such a tribunal expand its mandate to include drug trafficking?

This is the question that kicks of my newly published article, "Three International Courts and Their Constitutional Problems," which I mentioned yesterday. Consider this hypothetical:

Imagine the United States grappling with an outbreak of domestic terrorism. Many suspects are detained, but prosecuting them would be difficult because evidence was obtained in violation of the Fourth Amendment, or because the large number of defendants would clog the federal court system. Or consider U.S. policymakers confronted with the problem of closing Guantanamo Bay. Civilian trials in domestic courts are politically unpopular, but the detainees cannot simply be freed.

To deal with these problems, imagine the United States signs an "International Terror Tribunal Treaty" with Afghanistan, Jordan, Iraq, Morocco, Saudi Arabia, Turkey, the Netherlands, Israel, and the Marshall Islands. Those suspected of terrorism or material support of terrorism from any of the signatory countries would be tried by the International Terror Tribunal, composed of one judge from the high- est court of each country. Rules of process, proof, and punishment would be based on those of other prominent international criminal tribunals, and the due process rights of all defendants would be respected.

The International Criminal Court (ICC) … operates on the same underlying jurisdictional principles as the hypothetical International Terror Tribunal. If the United States were to join, it would delegate to the ICC jurisdiction to prosecute American nationals for crimes committed at home and abroad…

While the ICC is a largely novel international development, it is not the first time the United States confronted whether the Constitution permits participation in international courts with direct jurisdiction over citizens.