The New York Times > Opinion > Op-Ed Columnist: Missing in Action
It's all a worthwhile read, but the last three 'grafs are the money shots:

The sheer volume of missing documents, and missing recollections, strongly suggests to me that Mr. Bush blew off his Guard obligations. It's not fair to say Mr. Bush deserted. My sense is that he (like some others at the time) neglected his National Guard obligations, did the bare minimum to avoid serious trouble and was finally let off by commanders who considered him a headache but felt it wasn't worth the hassle to punish him.

"The record clearly and convincingly proves he did not fulfill the obligations he incurred when he enlisted in the Air National Guard," writes Gerald Lechliter, a retired Army colonel who has made the most meticulous examination I've seen of Mr. Bush's records. Mr. Lechliter adds that Mr. Bush received unauthorized or fraudulent payments that breached National Guard rules, according to the documents that the White House itself released.

Does this disqualify Mr. Bush from being commander in chief? No. But it should disqualify the Bush campaign from sliming the military service of a rival who still carries shrapnel from Vietnam in his thigh.