So why is it you won't declassify?

So there were 28 or so pages redacted from the 9/11 report, and apparently many of them dealt with the Saudi connection to the attacks. The Saudis feel that the mystery of what was involved is more dangerous to them than the disclosure of this information. But Bush has rebuffed the Saudis. Why? Apparently Senator Richard Shelby, who was the top Republican on the 9/11 inquiry, thinks 95% of the redacted portion could be declassified without endangering national security. So what gives?