The Pentagon is claiming it inadvertently destroyed military records from more than 30 years ago that could have definitively determined whether George W. Bush fulfilled his duty in the Texas Air National Guard. Questions have loomed for the past five years over whether Bush skipped out on his commitment during periods of 1972 and 1973. Yesterday in response to a Freedom of Information Request the Pentagon said for the first time that the microfilm containing Bush’s payroll records from the disputed period was ruined in 1996 or 1997 during an attempt to salvage deteriorating microfilm. Some journalists expressed skepticism about the Pentagon’s claim. James Moore, who wrote “Bush’s War For Re-Election” said, “Those are records we’ve all been interested in. I think it’s curious that the microfiche could resolve what days Mr. Bush worked and what days he was paid, and suddenly that is gone.”