The best essay I’ve seen that really drills into fascism - not just how it’s presented itself throughout history, but what it is at some fundamental level, and how the various fascisms of various states are interlinked - is Roderic Day’s Really Existing Fascism, which both explores fascism and also explains how Nietzche is its progenitor (although, as always, it’s more complicated than that) much like Marx was communism’s progenitor (of the non-anarchist variety, and again, it’s more complicated than that).

The most relevant part of the essay (though the whole thing is very good and worth reading):

spoiler

The model of an equilateral triangle, where each of liberalism, fascism, and socialism represents a different vertex, is incorrect. Rajani Palme Dutt’s claim that fascism represents “capitalism in decay” and “the death-rattle of the dying bourgeois civilization” also confuses things. [63] Fascism is as co-constitutive of capitalism as liberalism is. Liberalism corresponds to the operational aspect of surplus value exploitation in the core, whereas fascism corresponds to the operational aspect of primitive accumulation at its temporal and spatial boundaries.

A much-simplified — but still useful — version of the “stagist” Marxist model of historical development looks like this:

Primitive communism
Slavery
Feudalism
Capitalism
Socialism
Communism

Describing fascism as the “death-rattle” of stage four obscures the fact that it has been present from the outset. Fascism is just the operational aspect that the unlucky part of the globe gets to experience capitalism as. We need to expand the model into a second dimension to integrate this understanding.

I propose the following:

Primitive communism
Slavery [64]
Feudalism — Ideological superstructure in defense of divine right (monotheistic hereditary land claims)
Capitalism — Ideological superstructure in defense of individual genius (entrepreneurship, race science, will to power)
Expropriative aspect: Primitive accumulation, fascism.
Exploitative aspect: Wage labour, liberalism.
Socialism — Ideological superstructure in defense of mass consciousness (Soviets, democratic dictatorship of the proletariat, scientific socialism). Multiple aspects (e.g. “Socialism with X characteristics”)
Communism — Ideological superstructure no longer has any class or state content.

This model conceives of the Axis powers as failed fascist experiments in empire-building, and the North Atlantic empires as successful ones. Fascism as an accusation stops relying on a cartoonish depiction of the Nazis as a cautionary tale of a potential future dystopia. Instead, it captures the fact that vicious dehumanizing brutality is co-constitutive of the violent, white supremacist, “freedom-loving” Western worldview.

I’ve seen Umberto Eco’s checklist simultaneously be rejected and accepted by the left. Some will say that it’s non-Marxist and prefer not to use it, but if anybody here says “the enemy is both strong and weak,” nobody (that I’ve seen) rejects that rhetoric device. I think the list is… fine. It’s a useful object to create pipelines further left. It’s “fun” to go down the list and explain how each bulletpoint corresponds to a feature in American society, because some of those things are just so accepted that it’s like trying to tell a fish that water exists. But one mustn’t lose sight of the definition of fascism given above.

The left-liberal conception of fascism is pretty interesting and/or strange, though. As you say, “you see a lot of libs and liblefts calling America fascist, but then being asked how, and not being able to respond.” If you’re a liberal, and your entire conception of fascism is “It’s what Hitler did,” it is pretty confusing to call America fascist. Where are the death camps? Where is the dictator?

I think at least one of the big reasons why liberals get so confused about fascism - simultaneously opposing it yet fumbling around about definitions and comparisons; calling Trump a fascist and yet not violently opposing him - is that by being liberals, they don’t really fundamentally disagree with any of the tenets of fascism. The problems with Hitler are very easy to describe. How many of them could, if pressed, offer an explanation of why exactly Mussolini was bad, let alone Franco? The “trains ran on time” myth is very emblematic of this sort of begrudging respect that liberals have for fascism. And how many liberals could articulate why the genocide of Native Americans isn’t remembered with as much abject horror - never again! - as the genocide of European Jews? How many of them have positive or at least complicated impressions of Manifest Destiny, but shudder at the word Lebensraum?

In the liberal conception of reality, the Jewish people endured so much hardship that they deserved a state and endless money to protect themselves - could they explain why, without looking like fascists, the Native Americans don’t deserve this? Can they explain, without looking like fascists, why neither them nor Black Americans deserve reparations? Many strange contradictions abound due to the white supremacy hiding like a black hole at the center of liberal ideology. This black hole is not there by accident. In the essay I linked, it’s explained that liberalism came into being to excuse and justify slavery, essentially. Many of the top liberal figures (thinkers and leaders) had atrociously racist views. This cannot be dismissed as “people were racist back then” because no, not everybody was bigoted back then, unless you don’t consider people outside the West to be people (that white supremacy again!). Stalin, as the essay quotes, was against anti-semitism and had strong principles about why. He accepted hundreds of thousands of fleeing Jews at the same time that the US was sending ships full of Jews back to Germany, for a large number of their occupants to later die in concentration camps. Liberalism has no problem with fascism’s bigotry and atrocities, while socialism opposes it.

One of the major problems with basic political communication with liberals today is their denial of the principle contradiction (imperialism), as well as the anti-communist propaganda that has totally polluted their conception of reality and history, and talking about fascism is one of the best ways to illuminate the divide between liberals and socialists.