The female captain, with whom the married general admits having a three-year affair, says he twice forced her to perform oral sex while they were stationed in Afghanistan in 2011. Sinclair is believed to be the highest ranking U.S. military officer to ever face trial for sexual assault.
In a December letter sent by her attorney, the female captain opposed the proposed plea agreement. The Associated Press generally does not name those who say they were sexually assaulted.
Writing on behalf of her client, Capt. Cassie L. Fowler suggested the proposed deal would "have an adverse effect on my client and the Army's fight against sexual assault."
"Acceptance of this plea would send the wrong signal to those senior commanders who would prey on their subordinates by using their rank and position, thereby ensuring there will be other victims like my client in the future," Fowler wrote.
Though prosecutors deny any consideration was given to Fowler's comments about the potential political fallout of dismissing the sexual assault charges, the emails turned over to the defense Saturday show they did discuss the assertions made in the letter.
Lt. Gen. James Anderson, as the commander of the base, made the final decision to reject the plea offer. Testifying from Afghanistan by telephone, Anderson said the only thing he weighed to make up his mind was the opposition of Sinclair's primary accuser to the deal.
Last week, Pohl ruled against a defense motion alleging improper command influence after pressing Sinclair's lawyers to provide any evidence such interference took place.
As part of their trial preparations, the defense had repeatedly asked to review emails sent or received by lawyers and commanders involved with the case. Prosecutors had opposed handing over the emails.
But on Saturday, prosecutors did hand over the emails now at issue, saying they had just received them in recent days. By law, prosecutors are required to hand over any evidence that might be helpful to the defense.