Those atop the chain of command in the WH, military, and intelligence establishments deliberately ignored all the warning signs of an impending attack--a clever strategy of plausible deniability--which also served to betray those in charge as incompetent rather than complicit. In every major head through the chain of command on 9/11, from Norad to the military, we see a repeated theme of complicity through negligence and incompetence. After 9/11 incompetence was rewarded and whistle blowers silenced.
And if they're willing to concede that, you can damn well bet the case runs a lot deeper. It's like copping a plea to manslaughter because if it went to a jury, you'd get convicted of murder.