WASHINGTON -- As they move forward with the Tailhook case, the Navy and Marine Corps are having trouble turning the initial accusations of sexual harassment abuse at an aviators' convention into criminal charges or administrative punishment.
The accusations stem from a Pentagon report in April that accused 140 fliers of indecent exposure, assault and lying to investigators under oath, among other violations.
But the Navy has already dropped outright half of its 120 cases, largely for lack of evidence. Only five Navy cases and one Marine case have so far gone to a military grand jury or to a court-martial.
And although a Marine aviator has been charged in the best-known incident, the assault on a Navy lieutenant named Paula Coughlin, questions have now been raised that appear to undermine the prosecution's case.
The general lack of success has set off a round of finger-pointing among Navy prosecutors and civilian Pentagon investigators who provided the bulk of the prosecution's evidence.
In one instance, a young prosecutor was reassigned after recommending that all charges against a Navy lieutenant be dropped for lack of evidence.
The recommendation was rejected and the accused, Lt. Cole V. Cowden, now faces court-martial on charges of conduct unbecoming an officer.
Many lawyers on both sides say they fear that alcohol-impaired memories, a code of silence among many pilots and scanty physical evidence may produce only a handful of convictions, and that many offenders will go free.
The report of the Defense Department inspector general published in April found that 83 women had been assaulted during four days of debauchery at the Tailhook Association convention of naval aviators in Las Vegas, Nev.
But only two Navy fliers and one Marine officer have been charged with assault, leaving more than 40 others to be fined or reprimanded.
Pentagon investigators say the reprimands, at a time when the military is shrinking, will blight and probably end careers.
But military defense lawyers say in many cases the Navy's witnesses have declined to testify or have disputed the Pentagon's version of their earlier interviews, forcing prosecutors to drop dozens of other charges.
After two Navy investigations widely regarded as incompetent, the Pentagon inspector general issued a searing report outlining an evening of drinking, abuse and generally lewd behavior.
But military investigators say the Defense Department report was meant to be a narrative about what happened, not a guideline for indictments.
Senior Navy officials privately grumble that the inspector general's report sensationalized the scandal without giving prosecutors much new evidence beyond what the two discredited Navy inquiries contained.