In a statement posted on the WikiLeaks website, he said: "When communicating with the press is 'aiding the enemy' it is the 'general knowledge among the people' itself which has become criminal.
"Just as Bradley Manning is condemned, so too is that spirit of liberty in which America was founded.
"In the end it is not Bradley Manning who is on trial. His trial ended long ago. The defendant now, and for the next 12 weeks, is the United States.
"A runaway military, whose misdeeds have been laid bare, and a secretive government at war with the public. They sit in the docks. We are called to serve as jurists. We must not turn away."
More top news
One Leicestershire mother managed to get a shop worth £140.27 for just 39p, Jennifer Drew told Good Morning Britain how.
Women's rights campaigners have condemned the sentencing of Purvi Patel, who put her stillborn foetus into a bin after miscarrying at home.
Read the letter carefully, don't worry, it's short. Note that while it praises the Conservative-led government it does not mention Labour.