It's not surprising that many officials in Washington are talking about convening an independent panel to investigate the federal government's actions before the Sept. 11 attacks. ... Congressional investigations can calm public anxiety, push reforms upon government agencies and in some cases force out ineffective officials. What they are unlikely to do is give us the kind of understanding that normally comes only decades later from history, when we will have full access to information and the distance to judge it properly.

Presidential historian Michael Beschloss explains it all.

Fact-Finding and Its Limits