One of my working definitions of ideology lately has been to see ideology as the collapse of the self (or thought, or reason) into its contents. By this I mean something clear and very precise, but it's a little difficult to explain in words; essentially what happens is that the mind, which always posits many ideas and concepts and operates by valuing these in various combinatory ways, stops that value-process at the level of contents-ideas in active combination and instead descends to the level of the contents of those concepts-ideas, as if a content in question were actually the concept and idea toward which it contributes. Ideology is well known to be the fact that thinking stops and "brute facts" are asserted in the place of any former or possible critique. Appeal to brute facts is anti-rational and opens the way for pathology to grip the mind because of how the content without its proper form (the proper form of a content is, in this case, that concept and idea toward which it contributes) immediately dissociates from any form "above" itself (forms in reason) and makes itself freely available to act as a surrogate form for other things, namely for other contents.
This is how a feeling can link directly into a pre-conceptual content in order to generate what looks like a concept and idea but is in fact nothing at all like a concept and idea, it only shares a superficial image with conception and likewise reason is impossible to replicate at that level of the pure image. This loss of reason is the form of the pathological, while the content of the pathological is simply whatever false content-links are directly forged at the pre-conceptual level. Thesw contents must still be grounded in something, so that lacking any rational conceptual structures in which to meaningfully participate they instead find a loose grounding in other contents, in direct associations of proximity and power.
The issue of proximity is easy enough to understand, but what about the issue of power? This power is a power of the false linkage to release another content (including a feeling) into direct expression extra-rationally or I should say pre-rationally. Suddenly the mind experiences a freeing of inner contents (feelings, inclinations, biases, justifications, images and memories, desires, etc.) directly and as if "by magic", without any need for a rational order or meaning to it all. This form of subjectivity can become intoxicating, indeed it is the cause of many problems including religious insanity, trolling behaviors, and of course ideological thinking. This is what I mean by saying that the mind/thought/reason collapses into its contents: reason is suspended as being no longer useful or necessary since direct stimulation of various subjective-conscious contents of experience can be obtained simply by adhering to an open-ended, non-critical process of "mental ejaculation". And it isn barely even mental, more like simply low-key immediate subjectivity experience with minimal context or extended meaning.
I see this kind of ideology at work in both the political left and right in the US. I see it in Trump, although I could side with Zizek and say that Trump is nowhere near as bad as someone like Cruz in whom this pathological ideology has become complete and reason completely silenced. In Trump at least there is some extension beyond the ideological sphere into the real world of meanings and reason, even though as far as I can tell those extensions are flimsy at best. Trump still had his reason but it is playing the role of servant to his ideological "purity", and this purity of being entirely ideological is what is required to win votes from the right-wing side of politics now in the US (it also helps the left-wing to invoke pure ideologies, and Obama is a master at this; I believe Obama has rational structures extended from his ideology similar to how Trump does, in fact I think for Obama his ideological purity is actually a secondary function of that reasoning, yet he hides the reasoning and more often defers to the ideology sphere. Why? Because it works... Because as Zizek also said, most people do not want real democracy but to have the appearance of choice while also subtly being told how to vote; most people want to be able to act as if they do not know the harsh truths of the world, and democracy is like a large zone separating people from those truths. This is a "proper" function of democracy and Obama defers to this function, this is partly the cause for his evasions and lies and especially his use of ideology when he could instead have used reason. Trump and the politicos right wing, on the other hand, have abandoned this deferment to the proper role or democracy and instead decided to shove unwanted truths on people as a form of psychological breakdown and appearing to be a power-player. I would argue that it is because they have lost true power, by totally capitulating to pure ideology and abandoning reason as such, that now they are becoming the ones going for the shock value sucker punch to the gut approach).