U.S. military lawyers said Wednesday that Army Pvt. Bradley Manning, who is accused of passing secret documents to WikiLeaks, knew his actions were wrong as he had broken similar rules before.
A pre-trial hearing for Manning heard that he posted a video about his life on YouTube in 2008, but it was spotted and the "corrective training" he later received included guidance on how to protect sensitive intelligence files.
The 24-year-old soldier, who could be jailed for life over the WikiLeaks allegations -- the biggest security leak in American history -- used banned military buzzwords including "classified" and "top secret" in the video.
It was meant to assure his family that he was coping with army life but instead it led to disciplinary action that included Manning having to give a PowerPoint presentation outlining how intelligence leaks could aid U.S. enemies.
The military says the YouTube video is evidence that Manning was fully aware of the consequences when he released a huge cache of diplomatic cables and military logs to WikiLeaks, and the prosecution wants the YouTube video and the PowerPoint slides shown to the jury that will decide Manning's fate next year.
The publishing by WikiLeaks of the official documents triggered a diplomatic firestorm that hugely embarrassed American officials who were left to deal with the fallout of the disclosures, which also rankled key U.S. allies.
Manning was arrested in May 2010 while serving as an intelligence analyst near Baghdad and subsequently charged with "aiding the enemy," a charge that could result in a life sentence, and dozens of other counts of misconduct.
Capt. Angel Overgaard, acting for the government at the pre-trial hearing taking place at Fort Meade military base in Maryland, said Manning's actions over the YouTube video and the subsequent WikiLeaks revelations were comparable.
"The intent behind the two acts is sufficiently similar -- willful, and was damaging to the interests of the United States," Overgaard said, referring to Manning's PowerPoint slides, which are believed to list Al-Qaeda as the enemy.
"The evidence shows he did know the actions were wrong when he committed them," Overgaard added.
Manning's defense team, however, argued that if the YouTube video and the PowerPoint presentation was put before a jury there would be a substantial risk of prejudice which could damage their client's right to a fair trial.
The defense has consistently maintained that Manning is not guilty of causing "actual harm" over the WikiLeaks disclosures.
Manning's lead defense counsel David Coombs has previously suggested that his client aimed to shed light on government secrecy while carefully selecting what documents to release to WikiLeaks to avoid jeopardizing U.S. national security.
However the judge in the pre-trial hearing, Army Col. Denise Lind, last month barred Manning's legal team from citing evidence at trial that the United States suffered no such harm. That ruling was a major setback to the defense.
On Wednesday, Lind said she would consider the legal arguments before issuing a ruling on whether the video from 2008 and two other matters that were not openly discussed in court can be put before the eventual trial jury.
Manning, who is attending this week's hearing, has not yet entered a plea in the case and his trial is penciled in to start in February -- five months later than originally planned.
The latest three-day pre-trial hearing will wrap up on Thursday.