The sentencing hearing of US soldier Bradley Manning, which begins on Wednesday at Fort Meade, near Baltimore, is likely to last several weeks, legal experts say.
Judge Colonel Denise Lind will hear testimony from more than 20 defence and prosecution witnesses, who are expected to weigh in on Manning's motives and the effects of leaking government secrets.
Manning was acquitted on Tuesday of aiding the enemy - the most serious charge levelled against him - but he was found guilty of leaking classified government documents and 19 other counts, including espionage and theft, for his 2010 national security leaks to WikiLeaks, the anti-secrecy organisation.
Manning faces a maximum penalty of 136 years in prison.
After the verdict was announced on Tuesday, experts assessed Manning's legal recourse.
"This case is going to be reviewed automatically, and will likely be in the appeals process for several years," Yale military law professor Eugene Fidell told Al Jazeera.
Manning "would have a very good appellate argument if convicted of aiding the enemy," he said, adding that he "wouldn’t speculate, for the time being, on what [Manning's] arguments would be".
The American Civil Liberties Union called Tuesday's decision a gesture to scare future whistleblowers.
"Since Manning already pleaded guilty to charges of leaking information – which carry significant punishment – it seems clear that the government was seeking to intimidate anyone who might consider revealing valuable information in the future," the ACLU said in a statement emailed to Al Jazeera.
Meanwhile, Julian Assange, whose WikiLeaks organisation revealed Manning's data dump to the world, reacted negatively to the verdict.
"It is a dangerous precedent and an example of national security extremism," he told reporters at the Ecuadorean Embassy in London, which is sheltering him. "This has never been a fair trial."
Judge Lind's verdict follows about two months of testimony and evidence. Manning, a 25-year-old native of Oklahoma, admitted to sending more than 470,000 Iraq and Afghanistan battlefield reports, 250,000 State Department diplomatic cables and other material, including several battlefield video clips, to WikiLeaks while in Iraq in early 2010. WikiLeaks published most of the material online.
The video elements included footage of a 2007 US Apache helicopter attack in Baghdad that killed at least nine men, including a Reuters news photographer and his driver.
The WikiLeaks case is by far the most voluminous release of classified material in US history.
Manning said he sent the material to expose war crimes and deceitful foreign policy and that he didn't believe the information he handed over would harm troops in Afghanistan and Iraq or threaten national security.
21st century warfare
In closing arguments last week, defence attorney David Coombs portrayed Manning as a naive whistleblower who never intended for the material to be seen by the enemy.
J.D. Gordon, Former Defence Department Spokesman told Al Jazeera that Manning "should certainly face life in prison. I think he's a traitor. I think he represents 21st century warfare".
"Bradley Manning decided he would be the judge, jury and executioner to damage the United States," Gordon said, adding that "Manning’s material was used an enemy propaganda campaign."
Prosecutors described the young soldier as an anarchist hacker and traitor who indiscriminately leaked classified information he had sworn to protect. They said al-Qaeda leader Osama bin Laden obtained copies of some of the documents WikiLeaks published before he was killed by Navy Seals in 2011.
In bringing the charge against Manning, prosecutors cited the Civil War-era court-martial of Pvt. Henry Vanderwater, a Union soldier convicted in 1863 of aiding the enemy by giving a Virginia newspaper a command roster that was then published.
Coombs countered that the Civil War-era cases involved coded messages disguised as advertisements. He said all modern cases involve military members who gave the enemy information directly.
Additional reporting by Massoud Hayoun