Pfc. Bradley Manning pleaded guilty Thursday to 10 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. And, for the first time, he offered his rationale for the crimes.
In court, Manning detailed why and how he sent classified material to WikiLeaks, a group that facilitates the anonymous leaking of secret information through its website.
He said he passed on information that "upset" or "disturbed" him, but nothing he thought would harm the United States if it became public.
Reading a statement for more than an hour, Manning described his motivations, beginning with what he called "sigact tables," documents describing significant actions in Iraq and Afghanistan that he said represented the "ground reality" of both conflicts.
He said he'd become "depressed about the situation there" and made copies of the sigact tables in his secure workstation in Iraq. Then, he took them back to the United States and pondered what to do with them.
Manning said he first called The Washington Post. He spoke to a woman who he believed was a reporter and told her the kind of material he had. After five minutes, he got the impression she wasn't taking him seriously, he said.
He said he then called The New York Times and got nothing but answering machines, so he left a message and his phone number and e-mail address, but never heard back.
Manning said he finally decided to send them to the WikiLeaks organization.
"I believed if the public was aware of the data, it would start a public debate of the wars," he told the court.
Earlier Thursday, after Manning's guilty pleas, Army judge Col. Denise Lind asked the defendant 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, and Mark Morgenstein wrote this report in Atlanta.