Military prosecutors have requested that the judge reject such a defense for 1st Lt. Ehren Watada, said his attorney, Eric Seitz.
"I guess at that point, we don't have any defense to the missing movement charge" if prosecutors are successful, he said.
The rulings by the judge, Lt. Col. John Head, on the motions brought by military prosecutors and Seitz will frame the conduct of the proceeding when it starts Feb. 5. The pretrial hearing could last two days.
On June 22, Watada, 28, a native of Hawaii, refused to board a plane headed to the Middle East with members of his unit, the 3rd Brigade, 2nd Infantry Division. He publicly announced his intention to refuse two weeks earlier.
Fort Lewis announced Nov. 9 that Watada would be tried for missing movement and four specifications - or counts - of conduct unbecoming an officer for statements against the war during speeches and interviews.
If convicted, Watada could serve up to six years in prison and be dismissed from the military.
During an earlier hearing, witnesses testified on Watada's behalf that the invasion launched in March 2003 was illegal because President Bush never received permission from the United Nations Security Council for a pre-emptive war and that the authority granted by Congress was achieved by "means of fraud."
The investigating officer who recommended Watada face a court-martial wrote that it would be "very difficult" for Army officers to determine the legality of combat operations because of the complexity of U.S. and international law.
Meanwhile, the Army had subpoenaed two journalists to testify at the pretrial hearing but recently told them they're not needed. It still could order them to the stand during the court-martial.
"The Army has requested that they simply verify the accuracy of their stories, that their stories are an accurate representation of what was said during the interviews or during public appearances," said Joseph Piek, a Fort Lewis spokesman. "We're not asking them to provide notes or transcripts or anonymous sources or anything like that."
One of the journalists, Sarah Olson, said Wednesday that the subpoena puts her in an untenable situation of being a journalist participating in the prosecution of political speech. She added that it's unnecessary because the interview can be downloaded online.
"Ninety-seven percent of it at least is all there," said Olson, an Oakland-based freelance journalist. "I think they need to figure out how to authenticate this without using me."