[5] Couch was one of three prosecutors of U.S. Marine Corps pilots in three trials involving the collision of a military jet with a ski gondola system in Cavalese, Italy that caused the deaths of twenty European tourists.

[6]  Couch successfully prosecuted Marine Captains Richard J. Ashby and Joseph Schweitze for obstruction of justice in 1999 related to the destruction of video recordings of the incident.

[7] In 2001, Couch returned to active duty to prosecute Lt. Col. Odin F. Leberman, the commanding officer of the Marine Corps' only V-22 tiltrotor squadron for falsifying maintenance records.

[10] In January 2003, Couch served as lead prosecutor in the case of Lance Corporal Antoine Boykins, a parachute rigger who sabotaged the chutes of 13 fellow Marines prepared for a low-altitude jump near Camp Lejeune, North Carolina.

"[2] Later he learned that Slahi had been subjected to even worse interrogation methods, including beatings, prolonged isolation, extreme cold temperatures, and threatened with death as well as the arrest of his mother.

"[2] Inspired by the writings of Dietrich Bonhoeffer, a Protestant theologian who had been executed by the Nazis, and hearing the question if he would "respect the dignity of every human being" at a church service, Couch made the decision to refuse to prosecute.

[2] In 2004, Couch withdrew from Slahi's prosecution team because he believed he was asked to use evidence obtained through means of coercive interrogation that violated the Uniform Code of Military Justice, U.S. laws, and the United States' treaty obligations.

[4] After Wall Street Journal reporter Jess Bravin's article "The Conscience of the Colonel" was published on March 31, 2007, Couch received widespread recognition and international media coverage for his refusal to prosecute Slahi.

In 2021, a feature film based on Slahi's detention The Mauritanian[21] included the role of Lieutenant Colonel Couch as portrayed by the actor Benedict Cumberbatch.

[9]  In that role he served as liaison to Solicitor General Paul Clement who argued before the U.S. Supreme Court in the case Hamdan v. Rumsfeld (2006), related to the constitutionality of President Bush's authority to order prosecutions before military commissions at Guantánamo and applicability of Common Article 3 of the Geneva Conventions.

Couch left the Office of Military Commissions in 2006 and served on the U.S. Navy-Marine Corps Court of Criminal Appeals as a Senior Appellate Judge until his retirement in 2009.