Oral arguments on Bradley Manning's dismissal motion were scheduled at a pretrial hearing that opened Tuesday at the Fort Meade military base in Maryland. The hearing is expected to span three days.
Manning faces 22 counts, the most serious of which is "aiding the enemy."
His legal team says prosecutors have failed to meet their obligations to share information that could help the defense, and that therefore the entire case should be dismissed.
Manning's lawyers are also filing a specific challenge to the "aiding the enemy" charge. His attorney, David Coombs, says Manning is not specifically accused of planning to give intelligence to the enemy. He also wrote in a defense motion that his client "expressly disclaimed any intent to help any enemy of the United States" in online chat logs.
Manning is alleged to have leaked a trove of diplomatic cables and military documents related to Iraq and Afghanistan. If found guilty, he could spend the rest of his life in prison.
Prosecution experts testified during a preliminary hearing in December they found evidence Manning downloaded diplomatic cables onto compact discs that were sent to WikiLeaks.
Manning's lawyers have described their client as a troubled man who should not have been allowed access to classified material while serving in Iraq between November 2009 and May 2010. His attorneys also said the military's oversight of its computers was lax.
The leaked documents, published by WikiLeaks starting in July 2010, infuriated many in the international community, often providing blunt and unflattering U.S. views of world leaders' private and public lives.
U.S. officials say the WikiLeaks publication of the stolen documents put lives in danger, threatened national security and undermined American efforts to work with other countries.
