Contrary to the assertion of the March 5 editorial “A fair deal for a terrorist,” Majid Khan’s plea deal does not demonstrate that all is well with the military commission system. Instead, it underscores that trying cases before the military commission system remains a risky proposition on shaky constitutional grounds.

This system, now in its third incarnation, continues to face lengthy litigation over the legality of trying individuals for offenses that do not constitute war crimes. For example, Mr. Khan was charged with crimes such as terrorism and conspiracy that are not considered war crimes under international law and that were only later deemed crimes in the military commission system. Prosecuting people for conduct that was not a crime when they committed the act violates the ex post facto prohibition enshrined in the Constitution and the international legal principle of legality.

Mr. Khan’s plea deal is ultimately a loss for the integrity of the U.S. justice system and further evidence that the Guantanamo prison must close. As the Afghanistan war winds down, we Americans should learn from the mistakes of Guantanamo and recommit ourselves to our proven federal courts, local law enforcement and the Constitution.

Melina Milazzo, Washington

The writer is an attorney with Human Rights First.