The diminutive former intelligence analyst, wearing a green Army camouflage uniform, was mostly quiet through the first day of the hearing at Fort Meade as his civilian attorney tried to get the presiding officer thrown off the case.
After Almanza declined to step down, Coombs asked a higher military court to halt the proceeding and review the ruling. Almanza said he would continue the hearing while waiting for that court to respond.
Manning, who turns 24 Saturday, is charged with aiding the enemy and violating the Espionage Act in what has been called one of the largest security breaches in U.S. history. Aiding the enemy is a capital offense, but Army prosecutors have said they will not seek the death penalty. If convicted, Manning could be sentenced to life in prison.
It is not clear whether Manning will testify during the hearing.
The world's media gathered at the Army base in Anne Arundel County for their first live glimpse of Manning, who was unknown to the public when he was arrested in Iraq 18 months ago. He has been held in confinement ever since.
While Manning was out of sight, his case became a cause celebre among antiwar activists. They say the raw field reports from Afghanistan and Iraq, the diplomatic cables containing unvarnished observations of foreign leaders and the video footage of a 2007 helicopter attack in Baghdad that he is alleged to have disclosed should never have been classified and that Manning should be protected as a whistle-blower.
Some supporters made it into the courtroom Friday. Others spilled into an adjacent theater to watch the hearing on a closed video feed, and still more gathered outside the Fort Meade gate. After Almanza ended the hearing for the day, a man wearing a Veterans for Peace badge said, "Bradley Manning, you're a hero."
The Article 32 hearing is a preliminary proceeding to determine whether the case should go to court-martial. The investigating officer will weigh evidence, witness testimony and arguments before making a recommendation.
It was a start-stop session Friday, with Almanza declaring several breaks, and the parties spending more time in recess than in court.
Almanza asked Manning whether he understood the charges against him, understood his rights and was satisfied with his legal team. Manning answered each with a simple "yes, sir."
Almanza then asked whether either the defense or the prosecution objected to his participation in the hearing. Coombs rose. He said Almanza's civilian employment could cause a reasonable person to question his partiality in the military proceeding.
Almanza replied that the Justice Department is a large organization and that in his work in the child exploitation and obscenity section of the criminal division he has had no involvement in its investigation of Manning and WikiLeaks.
Coombs, who is himself an Army reservist, said Almanza's rulings against the defense raised further questions about his impartiality.
Almanza rejected all but two of 38 witnesses requested by the defense and decided to keep open a portion of the hearing that the defense wants closed. He also said he would accept statements from senior officers who will not be brought to Fort Meade for cross-examination.
Coombs said the ability to cross-examine those officers is important to Manning's defense, which he said would rely on questions about whether the materials he is accused of leaking should have been classified and whether their disclosure caused harm.
He said Almanza's employment, coupled with rulings that had gone consistently against the defense, could threaten public confidence in the proceeding.
"The questioning has already begun," Coombs said, referring to news coverage of the hearing published on the Internet during the day.
The Army prosecutors said they believe Almanza could be an impartial investigator.
Capt. Ashden Fein, the lead prosecutor, said a case cited by Coombs to argue against Almanza's participation applied to military judges at courts-martial, not investigating officers in Article 32 hearings, and stemmed from a proceeding in which the military judge was openly hostile to the defense.
After arguments and a 90-minute recess to deliberate, Almanza ruled that a reasonable person would conclude that he could be an impartial investigator. He then granted another recess to allow Coombs to contact the Army Court of Criminal Appeals with his request to halt the hearing and review the ruling.
That court, based at Fort Belvoir, Va., could respond at any time. In the meantime, the hearing is scheduled to resume Saturday and continue through Friday, if necessary.
Prosecutors are expected to begin presenting evidence Saturday.
Outside Fort Meade, former Army Lt. Dan Choi said Friday that the material Manning is alleged to have disclosed — which included the Apache helicopter video, in which Americans can be heard laughing and referring to Iraqis as "dead bastards" — helped to speed the withdrawal of U.S. troops.
The United States declared an official end to the war in Iraq on Thursday, the day before Manning's hearing began.
"We must have the truth to achieve justice — and without justice, we will never see true peace," Choi said.
The hearing marked a return to Maryland for Manning, who lived in Potomac and studied at Montgomery College before he enlisted in the Army in 2007.