The following is from the CIA's own publication "Studies 
in Intelligence," that was included in the book, Inside the
CIA's Private World: Declassifed Articles from the Agency's 
Journal, 1955-1992,"  edited by H. Bradford Westerfield. 

   The corrosion of intelligence analysis and reporting by political
action. "Individuals who work for an organization that displays a strong
commitment to a policy or outlook will be tempted to send back news which 
shows that they are on the right side, and to ignore or underplay 
uncomfortable facts so as not to risk unpopularity with their colleagues 
and superiors...if the intelligence service is dominated by a group of 
powerful decision makers, it will become a prisoner of these decision
makers' images, dogmas, and preconceptions. Instead of challenging these
dogmas and correcting these images when they clash with its objective 
findings, the intelligence service will be no more than a rubber stamp 
of these preconceptions. And who now will deny that nowhere is there a 
stronger "commitment to a policy or outlook" than by a service that is 
actively supporting a political faction, movement, or government with 
funds, advice, equipment, paramilitary resources and propaganda? 

   This observation should be uppermost in the minds of those
determining the future composition of the intelligence community -- but 
of course, it won't. The CIA is a policy implementing organization and
its intelligence in all cases relating to its policy is slanted,
distorted, or created to support those policies. Reporting on the
Vietnam War and the Soviet Union are examples of this phenomenon. 

Ralph McGehee
CIABASE