Army Col. Denise Lind released her legal rationale, or "special findings," as the sentencing phase of Manning's court-martial neared its end. Lawyers will make closing arguments Monday, and Lind said she would announce the sentence as soon as Tuesday.
Manning faces up to 90 years in prison for sending more than 700,000 military and diplomatic documents, plus some battlefield video, to the anti-secrecy group WikiLeaks while working as an intelligence analyst in Iraq in 2010. WikiLeaks published most of the material on its website.
Lind wrote in the 10-page document that Manning's actions were wanton and reckless.
"Pfc. Manning's conduct was of a heedless nature that made it actually and imminently dangerous to others," she wrote.
The rules for special findings require a written rationale only for guilty verdicts. Therefore, Lind provided no explanation for her decision to acquit Manning of the most serious charge, aiding the enemy. To have won a conviction on that charge, prosecutors would have had to prove that Manning knew the information he leaked would be seen by al-Qaida members.
On the espionage convictions, for transmitting defense information, Lind found that the leaked material was both potentially damaging to the United States and "closely held," meaning it had been classified by the appropriate authorities and remained classified at the time it was leaked. The defense had argued that much of the information Manning leaked either contained no damaging information or was already publicly known.
The lone computer fraud count on which Manning was convicted hinged on whether he knowingly exceeded his authorized access on a classified government network when he used his workplace computer to save the State Department cables to a CD so he could use his personal computer to transmit them to WikiLeaks.
The defense had argued that Manning was authorized to view the cables as part of his job, and that there was no prohibition on downloading or saving them. Prosecutors had argued that Manning had no authority to access such a wide range of cables since his job was narrowly focused on the threat from Shia Muslims in Iraq.
Lind drew a fine line in her legal reasoning. She said the phrase "exceeds authorized access" means Manning used the computer with authorization, and then used that access to obtain information he wasn't entitled to obtain.
The court-martial was in session for only about 30 minutes Friday. Prosecutors presented four bits of evidence retrieved from Manning's personal computer, mostly communications with his friend, Danny Clark, a Cambridge, Mass., computer expert. The contents of those communications weren't revealed in open court.
A military psychiatrist who examined Manning after his arrest testified Wednesday that Clark was unavailable to Manning when Manning leaked the material under great psychological stress, largely due to his gender-identity uncertainty at a time when gay service members were prohibited from serving openly.
Manning "felt in hindsight that if he'd been able to talk with Danny Clark, that might have prevented these acts because he felt like, 'If Danny had told me not to do that, I definitely wouldn't have done that,'" the psychiatrist, Navy Capt. David Moulton, testified.
Clark did not respond Friday to telephone and email queries from The Associated Press.
Manning apologized Wednesday for the harm he caused by leaking the information. He did not apologize, though, for exposing what he considered wrongdoing by the U.S. military and duplicitous diplomacy by the State Department.
Speaking to Manning supporters after Friday's session, defense attorney David Coombs acknowledged that Wednesday had been a tough day for Manning because it was "family day." There was testimony that day from Manning's older sister and an aunt, who both spoke of his difficult childhood with an alcoholic mother and the eventual split of the family after his parents divorced. Then the soldier got to spend about an hour and a half with family after Wednesday's session, Coombs said.
Coombs said Manning was in good spirits Friday. The lawyer was answering questions outside the courtroom from a couple dozen supporters who had attended Friday, including queries about Manning's apology and what Manning's conditions of confinement were like at the military prison at Fort Leavenworth, Kan., where he has been held for some of his pre-trial confinement.