Not an expert on the subject by any means, but I think it boils down to the Catholic Church (and therefore it’s extensions such as The Vatican, The City of London, and the Washington D.C. autonomous zone, and many others) being a front for the Jesuits, the militaristic and expansionist branch of the church leadership.

Things have come to a head recently as instead of ruling from the shadows (the black pope, search that term), the current pope is a Jesuit. I’m not completely convinced however, as I see the control system they currently operate as long predating the Catholic Church.