It's not what Trump says it is. Check out The Deep State: The Fall of the Constitution and the Rise of a Shadow Government, by long-time Washington insider Mike Lofgren. The Deep State is a grouping of some (not all) federal agencies, plus some private corporations, mainly in Silicon Valley. It remains in power no matter how elections go. Its political function is to police the boundaries of the Overton Window and prevent serious consideration of anything that falls outside the "Washington Consensus" -- neoliberalism in economic policy, neoconservatism in foreign policy. That's frustrating to anyone who wants any fundamental change, but it's hardly alarming or sinister.
See also here, also by Lofgren:
See also here, also by Lofgren:
There is little evidence that America will be saved by concealed and powerful forces in the manner of the shadowy Caped Crusader rescuing Gotham City from the deranged Joker, or, alternatively, that the rough-hewn populist good guy Trump is in mortal combat with the Deep State. It is true that he ran as a populist against elite institutions: the power centers of the 1 percent — Wall Street, Silicon Valley and the military-industrial complex — mostly supported his opponent. But his actions so far have strongly reinforced rather than weakened their position.
A glance at the membership of the president’s Strategic and Policy Forum shows they are flocking to his side, with masters of financial buccaneering like Stephen Schwarzman of the Blackstone Group and Jamie Dimon of JPMorgan Chase, along with Doug McMillon of retail giant Walmart. There is even an ex-governor of the Federal Reserve Board, Bush appointee Kevin Warsh. This is hardly a populist revolution of the kind preached by John Steinbeck’s Tom Joad.