I’m not sure if he coined the term (I can’t tell who did), yet Michael Parenti explains the concept quite eloquently here in his book Dirty Truths, in 1996, no less:

Often the term “conspiracy” is applied dismissively whenever one suggests that people who occupy positions of political and economic power are consciously dedicated to advancing their elite interests. Even when they openly profess their designs, there are those who deny that intent is involved.

Those who suffer from conspiracy phobia are fond of saying: “Do you actually think there’s a group of people sitting around in a room plotting things?” For some reason that image is assumed to be so patently absurd as to invite only disclaimers. But where else would people of power get together – on park benches or carousels? Indeed, they meet in rooms: corporate boardrooms, Pentagon command rooms, at the Bohemian Grove, in the choice dining rooms at the best restaurants, resorts, hotels, and estates, in the many conference rooms at the White House, the NSA, the CIA, or wherever. And, yes, they consciously plot – though they call it “planning” and “strategizing” – and they do so in great secrecy, often resisting all efforts at public disclosure. No one confabulates and plans more than political and corporate elites and their hired specialists. To make the world safe for those who own it, politically active elements of the owning class have created a national security state that expends billions of dollars and enlists the efforts of vast numbers of people.”

Yet there are individuals who ask with patronizing, incredulous smiles, do you really think that the people at the top have secret agendas, are aware of their larger interests, and talk to each other about them? To which I respond, why would they not? This is not to say that every corporate and political elite is actively dedicated to working for the higher circles of power and property. Nor are they infallible or always correct in their assessments and tactics or always immediately aware of how their interests are being affected by new situations. But they are more attuned and more capable of advancing their vast interests than most other social groups.

The alternative is to believe that the powerful and the privileged are somnambulists, who move about oblivious to questions of power and privilege; that they always tell us the truth and have nothing to hide even when they hide so much; that although most of us ordinary people might consciously try to pursue our own interests, wealthy elites do not; that when those at the top employ force and violence around the world it is only for the laudable reasons they profess; that when they arm, train, and finance covert actions in numerous countries, and then fail to acknowledge their role in such deeds, it is because of oversight or forgetfulness or perhaps modesty; and that it is merely a coincidence how the policies of the national security state so consistently serve the interests of the transnational corporations and the capital-accumulation system throughout the world.