Anderson, 27, was set to begin his court martial Monday on charges he tried to help the terrorist group. The trial at Fort Lewis, south of Seattle, was expected to last five days.
Anderson pleaded innocent Aug. 9 to five counts of trying to provide the al Qaeda terrorist network with information about U.S. troop strength and tactics, as well as methods for killing American soldiers.
Anderson, a member of the Washington National Guard's 81st Armor Brigade now in Iraq, faces life in prison without parole. A conviction requires agreement by two-thirds of a panel of commissioned officers.
Anderson, a Muslim convert, has requested that his general court martial be heard by commissioned officers rather than a judge or a mixed panel of officers and enlisted soldiers.
"He's making a tactical decision. They believe the officers, given this type of charge, will give him the fair shake," said David Sheldon, a Washington, D.C., attorney who specializes in military law.
Specifics of the case have been guarded, with Anderson's attorney, Maj. Joseph Morse, and military prosecutor, Maj. Chris Jenks, refusing to comment.
It's not known what evidence the defense will offer or who will testify on Anderson's behalf.
In June, Morse was denied a request that the government pay for a psychologist to help prepare his case. Judge Col. Debra Boudreau said the defense was free to pay one on its own.
Fort Lewis officials have not said whether Anderson has undergone a psychological evaluation.
Such an expert would help determine whether Anderson understands his conduct was wrong, said Sheldon, and therefore whether he should be held criminally responsible.
"In any federal court where this type of issue was litigated an expert would be provided," Sheldon said. "In a military court, sadly, this type of result is the routine, not the exception."
Anderson was raised Lutheran but began studying Islam while attending Washington State University.
Anderson complained in a November 2002 letter to the Herald of Everett about bigotry in the United States.
"In my three years as an observant Muslim, I've encountered nothing but kindness, patience, courtesy and understanding from them," he wrote. "On the other hand, I have experienced bigotry, hatred and mindless rage from so-called 'educated thinkers' here in the U.S."
Anderson caught the attention of federal agents last year with help from a Montana city judge, Shannen Rossmiller.
Rossmiller, of Conrad, Montana, testified at Anderson's military hearing in May that she monitors the Web for signs of extremist or terrorist activity. She said she came across a posting in October on a Muslim-oriented site by an "Amir Abdul Rashid."
Several Internet searches linked the name and e-mail address to Anderson, she said. Rossmiller said that when she posted a phony declaration for jihad against the United States, Rashid wrote back.
"He was curious if a brother fighting on the wrong side could join or defect," she testified.
Soon Anderson was text messaging a federal agent he believed was a member of al Qaeda. The conversations culminated in a meeting with two undercover investigators at a parking lot near the Space Needle in Seattle. The hour-long discussion was secretly recorded Feb. 9, just days before Anderson was to deploy to Iraq.
On the video, Anderson offers sketches and information about weaknesses in the M1A1 Abrams, the Army's primary battle tank.
"While I love my country, I think the leaders have taken this horrible road," he said on the video. "I have no belief in what the American Army has asked me to do. They have sent me to die."
Anderson was arrested at Fort Lewis three days after the meeting.