Benjamin H. Friedman lists the reasons think tank analysts lack intellectual independence. Think tanks are shaped by five forces creating political bias:
The first is institutional funding. If you take government or industry money, you will hesitate to undertake research that offends your sponsors. Many people see foundations as somehow cleaner money, but they too have agendas. Even those of us that rely on donations from many individuals of an ideological persuasion get selected to advance that ideology and thus cannot much violate it.
Second, personal profit biases ideas. Many defense and homeland security experts, especially the most prominent ones, work for defense contractors or investment companies in that industry.
Third is ambition. Those concerned with defense analysts’ independence tend to focus on money, but as Hans Morgenthau tells us, power matters more. Analysts tend to reflect the views of one party because they hope to serve it or because their employer does. Those pining for jobs in the Obama or Thune administration are not going to tell you exactly what they think about Afghanistan without considering how their would-be bosses would react.
A fourth bias in defense analysis is what academics call a selection bias. Just as people that go into the international development business are likely to support increased foreign aid, defense analysts are more likely than most to be hawkish people.
Fifth is social convention. When these pressures point in a particular direction, it seems impolite and for many people uncomfortable to swim against the tide. And we unconsciously adjust our political views to fit in with those around us.