Manning is charged with leaking 700,000 classified government documents to the Internet outfit WikiLeaks and was arrested in May 2010 while serving with the Marine Corps in Iraq. Military officials there did not hold Manning in solitary confinement but when he was returned stateside to a base in Quantico, Va., medical personnel termed him a suicide risk and ordered him held alone.
Manning's lawyer argued the e-mails between Marine Corps officials will show a conspiracy to keep his client from speaking to others while being held.
Courthouse News Service reported Wednesday Manning's lawyer has asked the military judge to dismiss the charges against Manning because of his treatment while awaiting trial.
International humanitarian agencies including the U.N. Special Rapporteur on Torture, have criticized the U.S. military for its handling of the case. In total, Manning has been held for two years without a trial, including the nine-month stint in solitary confinement at the Quantico brig, which has since been closed.
Manning's lawyer said his client's detention was not for protection, but to prevent any news of the proceedings from becoming public.
"They used their desire not to have negative publicity to have my client in a hole for nine months," said Manning's lawyer, David Coombs said.