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The term deep state has been around for a lot longer than mainstream conservative outlets have been using it, and it is not a conspiracy theory, it’s a concept used in political analysis. It points to the undeniable fact that power exists in America that is not answerable to voters in the form of intelligence agencies, security agencies, the donor class, the military industrial complex, and the mainstream media, and the undeniable fact that there is some degree of collaboration across these groups. How much collaboration and what form it takes is up for debate, but there is no legitimate case for it not happening.