(Adds details from court testimony and new quotes throughout)
By Colleen Jenkins
FORT BRAGG, N.C., March 6 (Reuters) - A U.S. Army general pleaded guilty on Thursday to military crimes of having an adulterous affair, asking junior female officers for nude photos and possessing pornography on his laptop while deployed in Afghanistan.
Brigadier General Jeffrey Sinclair, the defendant in a rare court-martial against a top U.S. military officer, stood firm in his resolve to fight charges that he sexually assaulted a female captain during their three-year relationship.
Sinclair, 51, a married father of two, said the affair with the woman 17 years his junior was consensual throughout, but he agreed it was inappropriate by military standards.
"I was a senior leader; she was a subordinate leader," he told the court in Fort Bragg, North Carolina, where he remains on active duty.
Sinclair was stripped of command in southern Afghanistan in May 2012 as a result of the criminal allegations.
He also pleaded guilty to trying to impede military justice after learning he was being investigated, deleting an email account that contained nude photographs of a civilian woman whom he described as a childhood friend.
For his admissions to wrongdoing, the decorated officer faces up to 15 years in prison, dismissal from the Army and forfeiture of pay and allowances.
"He accepted responsibility for his conduct," lead defense attorney Richard Scheff told reporters. "He's been waiting for this day."
Lawyers will lay out their cases on the remaining charges in opening statements scheduled for Friday. A jury of five two-star generals will decide Sinclair's case.
The stakes remain high. Sinclair could be sent to prison for life if convicted of the most serious charge, forcible sodomy.
The U.S. government alleges he twice forced the unmarried captain to perform oral sex, and on other occasions grabbed her groin and genitalia against her will.
Sinclair is accused of indecent conduct by having sex with the captain in public places, including a car in Germany, a hotel balcony in Arizona and an office with the door open in Afghanistan, the government said.
Prosecutors say he used his superior rank to prevent the woman from ending their sexual relationship and threatened to kill her or her family if she exposed the affair.
The general denies committing any sex crimes.
Sinclair's lawyers argue that text messages and the captain's journal entries reveal mutual affection between them and a romance that unraveled because of the woman's jealousy.
"It reflects what was in her mind at the time," said Scheff, a civilian attorney who is chairman of the Montgomery McCracken law firm in Philadelphia. "And it's a completely different story than what's in the charge documents."
WORKED RELATIONSHIP TURNED SEXUAL
As part of his plea to lesser offenses, Sinclair spent more than an hour on Thursday describing for the court the misdeeds that landed him there.
He said what began as a close working relationship with a female captain in Iraq evolved into a sexual affair that he claimed she initiated. During a later deployment to Afghanistan, she was assigned to his unit at his request.
"What made you think she wanted to have sexual relations?" asked the trial judge, Colonel James Pohl.
"Probably when she took her top off, Sir," said Sinclair, describing what he said was her initial proposition to have sex that he refused.
The general said he got "way too personal" with two other junior officers, exchanging sexually explicit emails and asking them to send him nude photos.
He said he viewed pornographic images and videos on his personal laptop that he brought overseas and attempted to have an inappropriate relationship with a female first lieutenant who rebuffed his request for a date. Sinclair said he was smitten by her and wanted to take her horseback riding.
Pohl accepted the guilty pleas and then granted motions by prosecutors to dismiss two other allegations.
Sinclair's defense attorneys say military leaders trying to look tough on sex crimes have pursued the case despite weak evidence and allegations made by a jilted ex-lover with questionable credibility.
The trial takes place as Pentagon officials are under orders from President Barack Obama to review how the military handles sex crimes after a spike in reports of non-consensual sexual contact.
(Reporting by Colleen Jenkins; Editing by Gunna Dickson)