The example below of Armstrong Williams-type shills being paid directly by the Bush administration is surely only the tip of the propaganda mill iceberg. It is very easy for administration fundraisers to get corporate or other donors to support the adminstration by say, making donations to AEI or the Claremont Institute or the Heritage Foundation, earmarked for a "chair" for a particular shill who will then go on radio and tv to perform as a paid liar and propagandist for Bush's Perpetual War to End Tyranny on the Planet, Starting With the Middle East But Getting Around to Africa and Asia Eventually, Someday, Maybe.
Democrats do this by having donors give money for chairs at Harvard and other elite schools, so that their meagerly educated spin doctors and sychophants can have the prestige of the Ivy League. Republicans are mostly shut out of the Ivy League, so they do the same at various think tanks. Billy Kristol used to teach at Harvard, though, since as Paul Gottfried has pointed out, neocons are really the "acceptable-to-the-Left" opposition that is hardly any opposition at all.
