"As Lincoln wrote to James Conkling in August 1863, "I think the Constitution invests its commander-in-chief, with the law of war, in time of war." In addition to the commander-in-chief clause of Article II, Lincoln found his war power in his presidential oath "to preserve, protect, and defend the Constitution of the United States."

Second, the various new substitutes for "unlawful enemy combatant" abolish an important distinction in traditional international law. As the eminent military historian Sir Michael Howard argued shortly after 9/11, the status of al Qaeda terrorists is to be found in a distinction first made by the Romans and subsequently incorporated into international law by way of medieval and early modern European jurisprudence. According to Mr. Howard, the Romans distinguished between bellum (war against legitimus hostis, a legitimate enemy) and guerra (war against latrunculi, pirates, robbers, brigands and outlaws).

Bellum became the standard for interstate conflict, and it is here that the Geneva Conventions were meant to apply. They do not apply to guerra. Indeed, punishment for latrunculi, "the common enemies of mankind," traditionally has been summary execution."

Read the rest at The Wall Street Journal.

Thanks NLT.