While denying that accusation, lawyers for the married father of two have said he carried on a three-year extramarital affair with the junior officer during war tours in Iraq and Afghanistan. The admission of an affair will almost certainly end his Army career.
Sinclair, 51, has pleaded not guilty to eight criminal charges including forcible sodomy, indecent acts, violating orders, and conduct unbecoming an officer and a gentleman.
The case against Sinclair, believed to be the most senior member of the U.S. military ever to face trial for sexual assault, comes as the Pentagon is already grappling with a troubling string of revelations involving rape and sexual misconduct within the ranks.
In pretrial hearings, prosecutors have painted Sinclair as a sexual predator who abused his position of authority to prey on a subordinate trained to follow his orders. They also say he threatened to kill her and her family if she told anyone of their relationship.
The Associated Press does not publicly identify the alleged victims of sexual assaults.
Sinclair's defense lawyers suggest it is the general who is the victim, both of a jealous ex-lover and of overzealous prosecutors facing intense pressure from top military and political leaders to send a message that sexual misconduct will not be tolerated.
The lead military prosecutor resigned just weeks before the start of the court martial, following a contentious pre-trial hearing in January where the defense contends the female captain perjured herself on the witness stand. A new prosecutor is now forging ahead with the case.
"We're in a remarkable place," Richard Scheff, Sinclair's lead defense lawyer, said this week. "The chief witness lied under oath. The lead prosecutor resigned because he found her untruthful and non-credible. The Army's senior leaders agree with his assessment. And yet we're going to trial."
Prosecutors have declined to comment about the case outside court proceedings.
It is extremely rare for such a high-ranking military officer to face a jury. Under the military justice system, members of the panel must be senior in rank to the accused — ensuring that Sinclair will be judged by a jury of generals.
The trial is on the docket through March 28.
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