The court-martial trial begins Monday for Bradley Manning, the Army private who has already admitted to sending more than 700,000 war-related and other classified U.S. documents to WikiLeaks.
The trial in the 3-year-old espionage case begins after months of pretrial hearings and will be held in Fort Meade, in Maryland, about 30 miles north of the White House.
Pfc. Manning is charged with indirectly aiding the enemy by causing classified material to be published on WikiLeaks, which carries a maximum sentence of life in prison.
Manning has admitted to sending the material to WikiLeaks -- an online, non-profit group that publishes secret and classified information from anonymous sources. He did so after accessing a supposedly secure government computer network, then downloading the information -- Afghan and Iraq battlefield reports, State Department cables and video of a U.S. Apache helicopter attack that killed a Reuters news photographer and his driver.
The 25-year-old Manning said in a statement in February that he leaked the material because he wanted the public to know how the American military was fighting wars in Iraq and Afghanistan with little regard for human life.
He got the information while working as an intelligence analyst in Baghdad in 2010.
Manning, an Oklahoma native, faces a total 22 counts.
Last week, Manning's lawyers said they had reached a deal that may eliminate the need for testimony from a member of the military team that killed Al Qaeda leader Usama bin Laden.
Prosecutors also agreed to accept Manning's guilty plea to a lesser version of one of the counts.
Under the agreement, the prosecution and defense teams would acknowledge evidence at the trial that indicated bin Laden saw some of the material Manning released. The raid team member, presumably a Navy SEAL, was expected to testify that the evidence was recovered during the May 2011 raid that killed bin Laden inside his compound in Abbottabad, Pakistan.
However, the deal must be approved by military judge Army Col. Denise Lind, who also presided over the pretrial hearings.
The trial is expected to last through the summer.
Prosecutors have already changed their minds about trying to convict Manning of violating the federal Computer Fraud and Abuse Act in connection with the release of a State Department cable known as Reykjavik-13.
WikiLeaks posted the cable in early 2010 about a meeting in Reykjavik, Iceland, summarizing U.S. Embassy discussions with Icelandic officials about the country's financial troubles.
Manning said in his Feb. 28 confession that he thought the cable indicated the United States was refusing to help the Icelandic government "due to the lack of long-term geopolitical benefit."
The cable was the basis for a charge alleging violation of a federal law, which is punishable by up to 10 years in prison. Manning pleaded guilty in February to lesser versions of that and eight other offenses, acknowledging violations of military law that, in total, carry a maximum prison term of 20 years.
No reason has been given for the change regarding Reykjavik-13, and prosecutors said they will still try to convict Manning of other serious offenses.
To prove the charge of indirectly aiding the enemy, prosecutors must show Manning knew the material would be seen by Al Qaeda members.
Judge Lind has already ruled the trial will be closed for some of the testimony of 24 witnesses, to protect classified information.
She said an unusual "dry run" hearing with a sample witness on May 8 showed that alternatives to courtroom closure proposed by Manning's defense team would not have prevented a spillage of sensitive information.
Lind said redacted transcripts of the closed parts of the trial will be made publicly available, but she didn't say how long it will take to have the transcripts cleared for release.
Manning supporters have already begun to gather outside Fort Meade, holding a protest march Saturday at the main gate.
Protesters, including members of the Bradley Manning Support Network, carried signs, some reading “Free Bradley” and “Bradley Manning: Jailed for exposing war crimes.”
Daniel Ellsberg, who leaked the Pentagon Papers, also was among those showing support.
The Associated Press contributed to this report.