Given the exigencies, it was entirely understandable. There had been a massive sneak attack against the United States. Thousands of Americans had been killed. The enraged public demanded action. The president, bolstered by a full-throated demonstration of congressional resolve, unleashed the armed forces.

The enemy responded, in plots designed at the highest levels, by smuggling trained operatives into the United States to conduct bombing operations and other terrorist acts. The targets were civilians and civilian infrastructure. Nevertheless, the FBI, acting on precious intelligence derived from the interrogation of a terrorist, moved in. A United States citizen was apprehended—the enemy having recognized that co-opted Americans could more easily infiltrate a nation on heightened alert.

The government actions here, it is worth underscoring, were by domestic law enforcement authorities, not soldiers. The federal courts, moreover, were open and functioning. In such circumstances, post-Civil War legal precedent dictated the use of ordinary criminal procedure: trial in the civilian justice system. Disregarding this seemingly settled law, the president issued a controversial executive order: Wartime terrorist operatives would not be regarded as criminal defendants swaddled in the protections and privileges of the Bill of Rights. They would be deemed unlawful enemy combatants. They would not be given civilian trials with the full panoply of defendant-friendly rights; trials would be by military commission.

This scenario rings familiar to followers of our bumptious post-9/11 debate over the proper balance between liberty and security. Yet it is not the case of José Padilla,