Bradley Manning allegedly sent 250,000 diplomatic cables and 500,000 battlefield reports from Afghanistan and Iraq to Wikileaks in 2009 and 2010. In February, he pleaded guilty to 10 of the 22 charges but not to the most serious charge of aiding the enemy.
If found guilty of the more serious charges, the 25-year-old faces a maximum term of 154 years in jail. He was arrested in May 2010 while serving in Iraq and he has not denied leaking the documents.
Manning told a pre-trial hearing in February he divulged the documents to spark a public debate on the role of the US military and foreign policy.
What are the charges?
He faces 21 counts for leaking of hundreds of thousands of classified digital files to WikiLeaks. The most serious charge is aiding the enemy. He faces 14 counts relating to various elements of the WikiLeaks disclosures, as well as five counts of violating military computer rules - all of which add up to a possible maximum sentence of more than 150 years in military jail.
He has pleaded guilty to having transmitted digital information to WikiLeaks between 1 November 2009 and 27 May 2010 - a period in which he was working as an intelligence analyst at Forward Operating Base Hammer outside Baghdad.