In the footage, airmen laughed and called targets "dead bastards." A military investigation found troops mistook the camera equipment for weapons.
Besides the aiding the enemy acquittal, Manning was also found not guilty of an espionage charge when the judge found prosecutors had not proved their assertion Manning started giving material to WikiLeaks in late 2009. Manning said he started the leaks in February the following year.
Manning pleaded guilty earlier this year to lesser offenses that could have brought him 20 years behind bars, yet the government continued to pursue all but one of the original, more serious charges.
Manning said during a pre-trial hearing in February he leaked the material to expose the U.S military's "bloodlust" and disregard for human life, and what he considered American diplomatic deceit. He said he chose information he believed would not the harm the United States and he wanted to start a debate on military and foreign policy. He did not testify at his court-martial.
Coombs portrayed Manning as a "young, naive but good-intentioned" soldier who was in emotional turmoil, partly because he was a gay service member at a time when homosexuals were barred from serving openly in the U.S. military.
He said Manning could have sold the information or given it directly to the enemy, but he gave it to WikiLeaks in an attempt to "spark reform" and provoke debate. Counterintelligence witnesses valued the Iraq and Afghanistan war logs at about $5.7 million.
Coombs said Manning had no way of knowing whether al-Qaida would access the secret-spilling website and a 2008 counterintelligence report showed the government itself didn't know much about the site.
The defense attorney also mocked the testimony of a former supervisor who said Manning told her the American flag meant nothing to him and she suspected before they deployed to Iraq that Manning was a spy. Coombs noted she had not written up a report on Manning's alleged disloyalty, though had written ones on him taking too many smoke breaks and drinking too much coffee.