A US soldier who refused to go back to duty in Iraq did so partly because his unit was told to abuse Iraqi detainees, lawyers have told his trial.
Camilo Mejia says he would prefer jail to a return to Iraq
Staff Sergeant Camilo Mejia failed to return from a two-week leave last year and is being court-martialled at a Georgia army base for desertion.
The Florida national guardsman says he would prefer jail to a return to Iraq.
But Judge Gary Smith ruled that evidence about prisoner abuse was irrelevant to the desertion charge.
The trial coincided with the Baghdad court martial of military policeman Jeremy Sivits who was jailed for a year on Wednesday for the abuse of Iraqi prisoners.
Staff Sgt Mejia also faces a year in jail and a bad-conduct discharge if convicted.
The Florida National Guard is one of the units of part-time soldiers that has been sent to the Gulf.
Staff Sgt Mejia served in Iraq for five months until last October when he went on leave - and then failed to report back to his unit in Fort Stewart, Georgia.
Lawyers at his trial said he was disturbed by the shooting of civilians and the "abuse and torture" of detainees in a military prison camp near Baghdad airport.
Defence attorney Ramsey Clark said Staff Sgt Mejia's unit was ordered to use sleep-deprivation tactics with blindfolded detainees.
He sought to make a comparison with the trial of Sivits and others accused of abuses in Iraq.
"The United States is seeking to court-martial soldiers in [Iraq] for outrageous abuses at the same time it prosecutes a soldier halfway around the world because he did what he had a duty to do under international law," the Associated Press quoted Mr Clark as saying.
Prosecutors argued that witnessing prisoner abuse did not justify fleeing the army.
"This is about a soldier who deserted, who ran away," lead prosecutor Captain A J Balbo said.
"While he went into hiding, he never raised these issues. Instead he buried them in his conscientious objector packet."
The trial is continuing.