Questions Raised About Bush Guard Service WASHINGTON - New documents unearthed in the midst of the presidential campaign fill in some blanks but raise other questions about the sometimes mysterious and spotty story of President Bush's military service during Vietnam when he won a coveted spot in the Texas Air National Guard and avoided the war.    Reviving issues that have shadowed his political career, the documents show Bush ignored a direct order from a superior officer and lost his status as a Texas Air National Guard pilot more than three decades ago because he failed to meet military performance standards and undergo a required physical examination...