Conspiracy theorists don't just imagine improbable connections; they create them.

Many years ago I purchased a paperback copy of  Proofs of a Conspiracy by physicist John Robison (who also invented the siren [I'm sure there's a metaphor there somewhere]) at a library sale. For those not familiar:

Towards the end of his life, he became an enthusiastic conspiracy theorist, publishing Proofs of a Conspiracy ... in 1797, alleging clandestine intrigue by the Illuminati and Freemasons (the work's full title was Proofs of a Conspiracy against all the Religions and Governments of Europe, carried on in the secret meetings of Freemasons, Illuminati and Reading Societies). The secret agent monk, Alexander Horn provided much of the material for Robison's allegations. French priest Abbé Barruel independently developed similar views that the Illuminati had infiltrated Continental Freemasonry, leading to the excesses of the French Revolution. In 1798, the Reverend G. W. Snyder sent Robison's book to George Washington for his thoughts on the subject in which he replied to him in a letter:

        It was not my intention to doubt that, the Doctrines of the Illuminati, and principles of Jacobinism had not spread in the United States. On the contrary, no one is more truly satisfied of this fact than I am. The idea that I meant to convey, was, that I did not believe that the Lodges of Free Masons in this Country had, as Societies, endeavoured to propagate the diabolical tenets of the first, or pernicious principles of the latter (if they are susceptible of separation). That Individuals of them may have done it, or that the founder, or instrument employed to found, the Democratic Societies in the United States, may have had these objects; and actually had a separation of the People from their Government in view, is too evident to be questioned.

Modern conspiracy theorists, such as Nesta Webster and William Guy Carr, believe the methods of the Illuminati as described in Proofs of a Conspiracy were copied by radical groups throughout the 19th and 20th centuries in their subversion of benign organizations. Spiritual Counterfeits Project editor Tal Brooke has compared the views of Proofs of a Conspiracy with those found in Carroll Quigley's Tragedy and Hope (Macmillan, 1966). Brooke suggests that the New World Order, which Robison believed Adam Weishaupt (founder of the Illuminati) had in part accomplished through the infiltration of Freemasonry, will now be completed by those holding sway over the international banking system (e.g., by means of the Rothschilds' banks, the U.S. Federal Reserve, the International Monetary Fund, and the World Bank).

I never did more than skim the contents of the actual book. What caught my interest was the introduction which somehow managed to connect the late 18th century text on Freemasons and the French Revolution to mid 20th century conspiracy theories involving communists, intellectuals and Jewish bankers. That last point has become relevant once again, given some of the people close to the current administration.

I've always had a morbid fascination with fringe dwellers and I've noticed that they have an extraordinary gift for seeking out and drawing up on other similarly crazy peers. Remarkably, this sense of companionship and urge to collaborate frequently crosses over seemingly unbridgeable ideological differences. Right wingers too extreme for the John Birch society would find common ground with Maoists talking about evil industrialists. Proof of conspiracy was proof of conspiracy regardless of who was supposedly conspiring against whom.