* Move comes after general overturned jury conviction, sentence
* Counsel to consider whether commanders should have judicial review
* Any change could affect wide range of other cases
By David Alexander
WASHINGTON, March 11 (Reuters) - U.S. Defense Secretary Chuck Hagel has asked the Pentagon's top lawyer to review a recent sexual assault case and assess whether commanding officers should have the power under military law to overturn a jury verdict, according to a letter released on Monday.
The review could have far-reaching consequences for the military judicial system, which grants the "convening authority" - the general responsible for a court martial proceeding - the ability to review a verdict from a jury trial and modify or dismiss it.
A decision to change that provision of the Uniform Code of Military Justice could have an impact on virtually all military legal cases, from the trial of al Qaeda suspects at Guantanamo Bay to the prosecution of Private Bradley Manning, who is suspected of releasing secret documents to WikiLeaks.
Hagel ordered the review after Lieutenant Colonel James Wilkerson at Aviano Air Base in Italy had his sexual assault conviction overturned by a top commander who threw out his one-year prison sentence and dismissal from the Air Force and returned him to duty.
Lieutenant General Craig Franklin, the officer with final authority in Wilkerson's court martial process, reviewed the trial record and concluded that despite the jury verdict the evidence was insufficient to prove him guilty beyond a reasonable doubt.
The decision triggered outrage among some lawmakers on Capitol Hill because of concern the military has been slow to address the problem of sexual assault. It also coincided with an unraveling scandal at Lackland Air Force Base in Texas in which 59 recruits were assaulted by drill instructors.
Senator Claire McCaskill questioned top generals about the decision to overturn the verdict at a hearing last week and sent a letter to the Air Force seeking an explanation. Senators Barbara Boxer and Jeanne Shaheen wrote to Hagel seeking a review of the case.
"I believe this case does raise a significant question whether it is necessary or appropriate to place the convening authority in the position of having the responsibility to review the findings and sentence of a court-martial," Hagel wrote in a letter dated March 7 that was released by Boxer's office.
He said the fact that the verdict went to the top commander for review even before it had been addressed by "the robust appellate process" offered by the military justice code raised questions about the system.
Hagel, in his letter to Boxer and Shaheen, said he was committed to taking steps to stop sexual assault in the military, a major problem that affected more than 3,000 service members in 2011 and 80 students at the military academies in 2011-2012.
Hagel said that while the commanding officer in charge of a court martial is not required to give the reasoning for his decision, he had asked the Pentagon's general counsel and the Air Force secretary recommend to how the decisions could be made more transparent.
He also asked the general counsel and the services to look at the Wilkerson case and "report to me on whether the case points to changes that should be considered in the UCMJ, or in the military services' implementation of the UCMJ."
Hagel also directed the counsel to ensure that the role of the convening authority is considered by an independent panel being set up by Congress and the Pentagon to review the military's handling of sexual assault cases.
Boxer welcomed Hagel's response.
"I'm heartened that Secretary Hagel is taking immediate action to review the facts of this troubling case and acknowledges that it is high time to take a hard look at how the military handles sexual assault cases," she said in a statement. (Editing by Eric Walsh)