The lawyer, David Coombs, described the proposal in a blog post Wednesday night, Politico reported. Coombs told military prosecutors about the plea agreement at a hearing Wednesday at Fort Meade, Md.
Manning is charged with providing thousands of pages of classified documents to WikiLeaks, including diplomatic cables and military documents.
He faces 34 counts and has opted to be tried by a judge instead of a military jury.
"Pfc. Manning has offered to plead guilty to various offenses through a process known as 'pleading by exceptions and substitutions.' To clarify, Pfc. Manning is not pleading guilty to the specifications as charged by the Government," Coombs said. "Rather, Pfc. Manning is attempting to accept responsibility for offenses that are encapsulated within, or are a subset of, the charged offenses. The Court will consider whether this is a permissible plea."
Experts said Coombs and Manning appear to be making a case that the charges against the soldier are more serious than his actual conduct warrants. But prosecutors remain free to go to trial on the full list of charges if they wish.