A National Guardsman who refused to rejoin his unit in Iraq, saying he refused to take part in an "oil-driven war," pleaded not guilty to desertion Friday.

Staff Sgt. Camilo Mejia (search) of the Florida National Guard (search) faces up to a year in prison and a bad conduct discharge. His court-martial was scheduled for May 19 at Fort Stewart.

Mejia, 28, was gone without permission for five months. He emerged in Florida in October after a two-week furlough and criticized the war before turning himself in last month.

He has applied for conscientious objector status, but the Army pressed on with prosecution because he was gone so long.

Mejia said he was particularly upset over an incident in which his unit was ambushed and innocent civilians were hit in the ensuing gunfire, and another in which he said an Iraqi boy died after confusion over which military doctor should treat him.