Manning's intentions, sexual orientation raised in hearing (Video)
At the time the video was posted by WikiLeaks, the Pentagon called it a breach of national security and it was believed to be secret.
Although WikiLeaks had been posting sensitive information to the Web since 2006, release of the Apache video drew worldwide attention to the organization as it prepared to publish secret documents on the war in Afghanistan.
Manning's appearances Friday and Saturday in the Fort Meade courtroom mark the first time he has been seen in public after 19 months in detention.
The Oklahoma native comes to court in Army camouflage fatigues and wearing dark-rimmed glasses. Slight and serious, he takes notes during the proceedings.
An Army appeals court on Friday rejected a defense effort to have the presiding officer, Lt. Col. Paul Almanza, because of alleged bias.
Separately, lawyers for WikiLeaks and founder Julian Assange are asking the military's highest appeals court to guarantee two seats in the Fort Meade courtroom.
Manning's hearing is open to the public, with limited seating. Inside the courtroom, no civilian recording equipment is allowed. Instead of a judge, a presiding officer delivers a recommendation as to whether prosecutors have enough evidence to bring a suspect to trial. A military commander then makes the final decision.
The case has spawned an international support network of people who believe the U.S. government has gone too far in seeking to punish Manning.
More than 100 people gathered outside Fort Meade for a march in support of Manning, some holding signs declaring "Americans have the right to know. Free Bradley Manning" and "Blowing the whistle on war crimes is not a crime."
Todd Anderson, 64, said he drove from New York City to take part. "I think this man showed a great deal of courage, the kind of thing I wouldn't have the courage to do, and I really consider him to be a hero," Anderson said.
Juline Jordan, 46, said she flew in from Detroit just for the day. "I support what he did because he exposed some horrific war crimes and horrific things done at the hands of the United States government and the Department of Defense, and he's a hero for that," Jordan said.
In London, several dozen protesters from gay organizations, the Occupy London protest camp and other groups rallied outside the U.S. Embassy Saturday calling for Manning's release and offering birthday wishes.
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