Possibly the LaRouche movement.
Background. I don't know must about the LaRouche movement myself. I'm getting my info from <em>Alcoholics Anonymous: Cult or Cure</em>.
The content of the book is very uneven, with some parts being well reasoned and thought provoking and others (IMHO) being shaking-my-head laughable. One of the better parts includes a very practical definition of cult. It isn't written in terms of yes or no, but rather as a list of characteristics that cults tend to have.
They apply the definition to various organizations, one being the LaRouche movement. And they conclude that it's very cult-ish.