An Army lieutenant who refused to deploy to Iraq because he considers the war illegal abandoned his soldiers and disgraced himself and the service, prosecutors said Tuesday at his court-martial.

A lawyer for 1st Lt. Ehren Watada, however, argued that his client was acting in good conscience, based on his understanding of the war and military law.

"At most, he engaged in an act or form of civil disobedience," defense attorney Eric Seitz said in opening remarks. "No way does that add up to conduct unbecoming an officer."

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The military accuses Watada, 28, of Honolulu, of refusing to ship out with his unit and conduct unbecoming an officer for accusing the Army of war crimes and for attacking the Bush administration's handling of the war.

Although other officers have refused to deploy to Iraq, Watada is the first to be court-martialed. In 2005, Army Sgt. Kevin Benderman, an enlisted man, served 13 months in prison and was given a dishonorable discharge after refusing to ship out.

Prosecutor Capt. Scott Van Sweringen told the court Tuesday that by Jan. 1, 2006, Watada had concluded that the war was illegal and he could not deploy. Rather than keep the decision between himself and his superiors, Van Sweringen said, Watada released a video statement at a June news conference in Tacoma.

Soldiers in Watada's unit, the 3rd Brigade, 2nd Infantry Division, left for Iraq — "absent a leader they had trained with. Absent a leader they had trusted," Van Sweringen told the seven-member panel of officers hearing the case.

In the video statement, Watada had said: "The wholesale slaughter and mistreatment of Iraqis is not only a terrible and moral injustice, but it's a contradiction to the Army's own law of land warfare. My participation would make me a party to war crimes."

The panel will hear from three government witnesses, including Watada's battalion commander who has said Watada told him he intended to conduct a private protest, Van Sweringen said.

Seitz argued that the young officer had no choice but to go public after the Army refused his attempts for a solution other than going to Iraq.

Watada has admitted he didn't get on the plane and that he made the statements in question, Seitz told the panel.

"The question is ... why? What was his intent? How did he comport himself when he made those statements and took action?" Seitz asked.

Seitz planned to call Watada and a character witness, an Army captain who has known Watada for about two years. The captain has been brought back from service in Iraq to testify.

Outside this Army base south of Tacoma, a small group that included actor Sean Penn demonstrated Monday in support of Watada. A few others demonstrated against him, including one man who carried a sign calling Watada a "weasel."