Navarre said a guilty plea could also lead the judge or sentencing jury to view Manning in a favorable light.
"One of the goals of accepting responsibility is to curry favor," Navarre said.
The hearing continued Thursday on a defense request to have the case dismissed because Manning has not been given a speedy trial. It has been two years and five months since Manning's arrest. His arraignment came 635 days later, far in excess of the 120-day rule. Coombs contends military commanders rubber-stamped all prosecution requests for delays and improperly excluded other periods from the speedy-trial clock.
Army Col. Carl Coffman Jr., who approved those early delays, testified for the prosecution that they reflected the sensitive nature of the material Manning was accused of leaking. Defense psychiatric experts had to gain security clearances, and classified documents containing possible evidence had to be reviewed by their originating agencies, Coffman said.
He said those measures were meant to ensure that the proceedings were fair and thorough.
"We considered the rights of the accused from the beginning," Coffman said.
The speedy trial issue will be litigated further at upcoming hearings.