FORT MEADE, Md. – As a military prosecutor held up a knotted bedsheet in court, Pfc. Bradley Manning acknowledged on Friday that he fashioned a noose and contemplated suicide shortly after his arrest on charges of engineering the biggest leak of classified material in U.S. history.

The pretrial testimony appeared to support the military's argument that it was trying to protect the former Army intelligence analyst from harming himself by keeping him in strict isolation, taking away his clothes and shackling him when he was outside his cell.

Manning's lawyers argue that the conditions he experienced for nine months at the Marine Corps brig in Quantico, Va., amounted to illegal punishment, lasting well past the time he was having suicidal thoughts, and that the charges against him should be dropped as a result.