FORT MEADE, Maryland (CNN) -- Pfc. Bradley Manning pleaded guilty Thursday to half of the 22 charges against him, but not the major one, in what the government says is the largest leak of classified documents in the nation's history.
The Army intelligence analyst is accused of stealing thousands of classified documents while serving in Iraq. The material was then published online by WikiLeaks. The group, which facilitates the anonymous leaking of secret information through its website, has never confirmed that Manning was the source of its information.
Army judge Col. Denise Lind asked Manning questions to establish that he understood what he was pleading guilty to.
In addition, she reminded him that his lawyer had filed a motion to have the case dismissed on the grounds that he was denied his right to a speedy trial -- a motion that Lind denied Tuesday.
By entering guilty pleas, Manning loses his right to have an appellate court consider that ruling, if he chooses to appeal.
A military lawyer who follows the case told CNN the tactic is known as a "naked plea," or a guilty plea in the absence of a plea deal. The lawyer said that by using that strategy, the defense apparently hopes the government will feel victorious about the guilty pleas Manning has entered and won't go through the effort of a trial.
However, in previous hearings, the prosecution has said it intends to pursue convictions on the remaining charges.
If his case proceeds, Manning has asked for Lind, instead of the military equivalent of a jury, to decide his guilt or innocence on the 11 charges to which he pleaded not guilty.
The U.S. military initially detained Manning in May 2010 for allegedly leaking U.S. combat video, including a U.S. helicopter gunship attack posted on WikiLeaks, and classified State Department records. Manning was turned in by Adrian Lamo, a former hacker, whom Manning allegedly told about leaking the classified records.
In December 2011, Manning's Article 32 hearing, the military equivalent of a grand jury hearing to determine whether enough evidence existed to merit a court-martial, began. He was formally charged in February 2012.
After a military judge denied Manning's lawyers' motions to dismiss charges in April 2012, the process proceeded, with Manning's court-martial scheduled to begin on June 3.
Larry Shaughnessy reported from Fort Meade, Maryland, and Mark Morgenstein wrote this report in Atlanta.