I actually had a very productive discussion about fascism with a conservative friend of mine, which ended up discussing conservatism more generally. The more I think about it, the more I hate American discourse on these topics. We use all of these words so poorly.
The discussion had to do with my belief that Trump is fascist. His initial belief was that you could have a left-wing fascism. Even said you could describe the Soviet Union as fascist. (Apparently, by the way, "red fascist" was a real term some people used, although its usage was pretty limited to Trotskyist left wingers). I said I didn't think left fascism was possible. Given that I've become interested in the French Revolution lately, I began thinking about many of the terms, why they're used poorly in America, and how to better describe fascism.
-- Long ramble about the French Revolution incoming --
I think left vs. right, apart from economics, is best understood by knowing more history about the French revolution. Basically, there was a financial crisis in France, and the Third Estate, comprising the vast majority of French citizens, wanted a larger say in the Estates General, which you can kind of think as an emergency congress the king could assemble to deal with issues in a complex time. Given the tumultuous times, and the unwillingness of the army to cooperate with the king, eventually the Estates General, under the pretense of bringing rights to the French citizenry, basically declared themselves the new government of France. The king kind of went with it because he had no one willing to defend him.
Okay, so you had basically a loose group of people in some new amorphous government over France. The Estates General became very cliquish, and at first you had the more liberal, pro-democratic guys collecting together in the Breton club, who were able to force through a bunch of their ideas by working together. Eventually, the less liberal forces started working together. And as we all famously know, the more liberal forces sat on the left side of the assembly room, and the more conservative forces on the right.
Left and right were defined in this context. Specifically, it had shockingly little to do with economics - left and right economics came later. Early on it had much more to do with hierarchies, privileges and so forth. The left was for destroying old privileges - nobility were granted all sorts of tax exemptions, they could buy political offices (by the time of the French Revolution something like 90% of public offices were purchased), and could collect taxes. They were the ones pushing for an absolutely mandatory, exemption-free tax system to end France's budget problems, and to limit the power of the nobility.
-- End of ramble --
So, what left and right I think most purely mean is about the movement's relationship to the hierarchy: left-leaning movements are anti-hierarchy, right-leaning movements are pro-hierarchy. This is why, historically, conservatism, reactionary and right-wing forces get along - conservatives want to preserve, so they're a natural ally of hierarchies. Reactionary forces want to move the clock back before a liberal movement, and restore hierarchies which used to exist.
Interestingly, fascism is the first mass reactionary movement in an age where monarchism had truly died. Before fascism, being reactionary meant you restored the monarchy, or fought to protect noble privileges. WW1 pretty much ended the age of monarchies and nobility, specifically it more monarchies than any other single event in history.
Okay, so how does that pertain to the Soviets and fascists? Well, pretty easily. The reason you can't have left fascists is, fascists have historically always worked with entrenched power. German conservatives, like factory owners, were terrified of communism. They supported the Nazis because they saw the Nazis as the primary way to preserve their own hierarchy. Whereas the reds were in a civil war against the whites - the reds fought the civil war in direct opposition to every privilege of the old nobility in Russia.
That's why Nazi Germany, for instance, was regressive in women's rights. It wasn't because of any real belief in things, it was because men used to have a more dominant position over women, and in the liberal Weimar era, German women were freer. The Nazis forcefully and violently restored what was seen as the "proper order", the old hierarchies of men being firmly superior to women in the society.
I think people who really support Trump are, frankly, white people who want to assert a kind of superiority. Not even ideological superiority, for most there's no racist handbook. And they're not wrong in every way to feel bad about the situation they find themselves in; they feel dignity has been lost and their communities destroyed, and in many ways it's true. However, I think it's pretty clear that the way they're acting out on these feelings are by creating a culture of hostility towards those they want to be their social inferiors. They want to pick on blacks, Mexicans, women. They want to talk like Trump does about women and have no one mock them. Not because they have some kind of sexism burning inside of them, but because they want that inner satisfaction of knowing they can say what they want and nobody can say **** to them. It's about power and prestige.
Also, in America there's Conservatives and conservatives. Self-titled Conservatives are almost always *******s with little to say. That doesn't mean there's not valuable, generic conservatism in the more useful sense that's appreciable.