Politicization can manifest itself in many ways, but in each case it boils down to the same essential elements: "Almost all agree that it involves deliberately distorting analysis or judgments favor a preferred line of thinking irrespective of evidence. Most consider 'classic' politicization to be only that which occurs if products are forced to conform to policymakers' views. A number believe politicization also results from management pressures to define and drive certain lines of analysis and substantive viewpoints. Still others believe that changes in tone or emphasis made during the normal review or coordination process, and limited means or expressing alternative viewpoints, also constitute forms of politicization."
Center for the Study of Intelligence: https://www.cia.gov/library/center-for-the-study-of-intelligence/index.html
Studies in Intelligence (1992), v.36 no.5