Obama's White House Office of Information and Regulatory Affairs is run by Cass Sunstein. Sunstein and Vermeule's paper on conspiracies theories, e.g. JFK, TWA 800, global warming fraud, MLK killed by feds,concludes that some theories create problems for government to solve. Thus, government should target, undermine and silence those (false, not true) conspiracy entrepreneurs with, at least, censorship.
Nock prescribes the study of classical Greece and Rome for disciplining the mind. Thus equipped, current events can be put in perspective. Rothbard's The Anatomy of the State reveals the problem the state has in gaining support from the public. The majority must view their government as good and beneficial. Court historians are groomed to persuade the public to the state's position. Conspiracy theories breed skeptics.
Barnes and Beard wrote revisionist histories, importantly exposing truths and facts - often the reverse of what had been previously accepted. Revisionists have been blocked from documents about WWII and US Foreign Policy since 1933. Revisionists might reveal the US to be morally repugnant.