The court martial of sergeant Santos Cardona, 32, could prove more significant than 10 earlier abuse convictions of American soldiers because testimony is expected from Major-General Geoffrey Miller, who helped shape policies at Abu Ghraib.
Miller would be the highest ranking officer to testify in the cases. He was a commander at Guantanamo Bay prison, where captives from Afghanistan and Iraq are held.
Cardona is accused of maltreatment of prisoners, dereliction of duty and assault while allowing his dog to intimidate detainees in 2003 and 2004.
If convicted, he could be sentenced to more than 16 years in prison.
Cardona and another dog handler, Sergeant Michael Smith, who was convicted on similar charges in March and sentenced to 179 days in prison, allegedly tried to scare prisoners so badly they urinated and defecated on themselves.
Opening statements were delayed until Tuesday as Marine Lieutenant Colonel Paul McConnell, the presiding officer, reviewed a series of pictures the defence wants to use in its opening.
Captain Kirsten Mayer, the defence lawyer, said Cardona appears in some of the photographs, including one with a naked inmate.
Cardona's defence team is expected to argue that his use of the dog was condoned by his superiors.
Only specialists, sergeants and privates have been tried in the Abu Ghraib cases.
Cardona is accused of
maltreatment of prisoners
Harvey Volzer, Cardona's civilian lawyer, said during a 2003 trip to Abu Ghraib that Miller recommended using dogs during interrogations of detainees.
Colonel Thomas Pappas, the chief military intelligence officer at Abu Ghraib, has previously testified that Miller suggested using the technique on the theory that Arabs have a fear of dogs.
Pappas, who also is on the list to testify at Cardona's trial, wrote a memo in 2004 calling for an end to the use of dogs and recommended that dog handlers not be disciplined for abusing detainees.
Treatment of inmates in US military prisons abroad has been an embarrassing issue for the US since 2004, when photographs were leaked showing prisoners being abused and sexually humiliated by military personnel.