I would just add that when a government is pre-disposed to a certain worldview, and certain plans exist before solid data exists, they can give too much weight to some evidence, and not enough to others. This is especially problematic for a president who is admittedly not interested in information per se. Bush adds an extra filter or two to the aloready filtered info that is due to the way our intelligence agencies are set up.
There are many examples of how hierarchies and bureacracies frustrate the collection of information and its collation into 'pure' knowledge. And Zero's observation that the worldview of the leaders plays a significant part in distortions and frustration.
Some time ago, I read of a PhD thesis on the rise to power of the Chinese Communist Party which relied heavily on Japanese intelligence reports. The thesis apparently concluded that Mao's success was largely due to a failure of the Japanese, in the 1930s, to supply sufficient men and materiel, and to failings of the intelligence services themselves.
One doesn't know whether to laugh or cry about this; that Mao, the CCP, and the Chinese people themselves played a decisive role seems to have been ignored; the underlying reasons for their success surely have more to do with Chinese society etc than Japanese intelligence!
While the US Administration's (Ashcroft's?) attempts to hoover up vast amounts of data about individuals is surely abhorrent (if the reports I've read are accurate), the irony is that the vast amount of data may actually weaken the quality of the intelligence.
You are aware, of course, that any intellegence agency
has counter-intellegence agencies working against it,
and that what it secretely discoveres can easily be
gone or change before it is given a wider exposure.
Aspecialy in the 21st century.