HONOLULU -- The court-martial of Hawaii-born solider Lt. Ehren Watada began on Monday in Ft. Lewis Wash.

He could be sentenced to prison time for refusing to deploy to Iraq.

At the Honolulu Federal Building on Monday afternoon, demonstrators rallied in support of Watada. The Japanese American Citizens League and Code Pink Hawaii Women for Peace organized the rally.

In court, the military judge ruled that almost all of the defense witnesses will not be allowed to take the stand. The judge earlier ruled that Watada's attorney, Eric Seitz, would not be able to bring up the legality of the war in Iraq.

Seitz was planning to call several international and constitutional law experts, but the military judge ruled they would be irrelevant.

Outside the courtroom there were demonstrations for and against Watada. Among Watada's supporters was actor Sean Penn.

"All we can hope is that it makes people think, and I think that the 400,000 people in the streets of Washington are the beginning of a voice that's going to get louder and louder. The people out here today those already here in support of Lt. Watada," Penn said.

Opponents called Watada a weasel and demanded he be sent to jail.

"I spent 20 years in the army defending my right to do this. You think these people are going to scare me away? Not a chance," said Jeff Brigham, who protested against Watada.

Watada faces up to four years in jail. The trial is scheduled to continue.