On Twitter, I'm probably one of those who overuse the term "fascism", although I typically frame it as "left-fascism". (No doubt in the minds of leftists, this seems to be an oxymoron.) I was heavily influenced by Tom DiLorenzo's essay I think originally found on Lew Rockwell's site but I think it (or a variation thereof) is posted on FEE here or Mises Institute. I think it was originally published in 1994. At the risk of oversimplification, fascism is a softer version of socialism which pays lip service to capitalism or private property but subject to regulation by the State. In a classic sense, you can thank of price floors (e.g., minimum brokerage prices) and price caps (rent control, price gouging, wages and prices, etc.), occupational licensing, permits, FDA approvals, zoning and health regulations, certificate of need laws, food truck restrictions, and literally hundreds or thousands of other policies, in effect "planned capitalism". In effect, you hold nominal property ownership, but the government has de facto control over it in a pervasive sense, so-called "planned capitalism". Leftism in America is obsessed with micromanaging businesses for policy objectives. It's no accident that progressives like FDR openly admired Mussolini before his joining the Axis with Nazi Germany.
If you do a search query on Trumpism and fascism, you'll likely pull up dozens of posts, e.g., this one by C.J. Polychroniou and this oped from George Will. So I'll discuss the question somewhat differently than those authors who agree with me the two (fascism and Trumpism) aren't the same. I also like Berman's contrast between fascism and the right wing which provides some some relevant context for Trump's appeal.
The conventional leftist tends to look at the dark side of twentieth century interwar fascism: its violence, racism, intolerance, simplistic approach, and conspiracy theories. The left wing on Twitter is obsessed with portraying Trumpkins as white supremacists and "domestic terrorists" (the Jan. 6 temporary occupation of the Capitol). This is manifestly absurd; this is a country which twice elected a black POTUS. and Trump earned some 70M votes for reelection, including an increased percentage of some blacks and Latinos. and in some respects he's been the biggest POTUS supporter for the Jewish state of Israel, including recognition of Jerusalem as its capital. In a poll after the Charlottesville tragedy, less than 10% found neo-Nazi/white supremacist type views acceptable. According to the FBI, there were 7175 hate crimes in 2017, in the context of 1,247,321 violent crimes, and note this is a cumulative figure, not all race-based or exclusively (say, black) race-based victims. There is some evidence of a growing trend of relevant crimes and hate groups, which is of concern; we libertarians believe in the non-aggression principle.
This is not to say that there aren't elements which are similar in nature in terms of Trump's anti-immigrant populism. I can still remember Trump attributing Romney's 2012 loss to Obama on his "maniacal" self-deportation policy:
Romney "had a crazy policy of self deportation which was maniacal,” Trump told NewsMax.com. “It sounded as bad as it was, and he lost all of the Latino vote ... He lost the Asian vote. He lost everybody who is inspired to come into this country.”
You then move forward 3 years, and Trump makes immigration his signature issue for his Presidential campaign, never mind there had been a decline in unauthorized immigrants over the prior decade. His provocative charges that Mexico was dumping its prison population across the border certainly ranks with some of the stereotypes and big lies of the interwar European fascists, and his policy of migrant family separation seemed to contradict the long-standing GOP position promoting family values.
But immigration is only one piece of the puzzle; Trump had tapped into middle-class angst, not unlike how interwar Europeans. Take Trump's tariffs on Chinese and other foreign imports, his attacks on companies like Ford, Carrier and Nabisco for shifting some production abroad, his condemnation on globalism, his hostility to free trade, etc. Consider this excerpt from Berman on the rise of fascism in Italy:
In Italy, for example, the postwar period saw high inflation and unemployment, as well as strikes, factory occupations, land seizures and other forms of social unrest and violence. The Liberal Italian governments of the postwar era failed to adequately address these problems...Benito Mussolini and his National Fascist Party (PNF) stepped into the breach, taking advantage of the failure or ineffectiveness of existing institutions, parties and elites, and offering a mixture of ‘national’ and ‘social’ policies. Fascists promised to foster national unity, prioritise the interests of the nation above those of any particular group, and promote Italy’s stature internationally. The fascists also appealed to Italians’ desire for social security, solidarity and protection from capitalist crises. They promised therefore to restore order, protect private property and promote prosperity but also to shield society from economic downturns and disruption. Fascists stressed that wealth entailed responsibilities as well as privileges, and should be administered for the benefits of the nation. constituencies – businessmen, landowners, members of the middle class – abandoned them....The regime intervened extensively in the economy. As one fascist put it: ‘There cannot be any single economic interests which are above the general economic interests of the state, no individual, economic initiatives which do not fall under the supervision and regulation of the state, no relationships of the various classes of the nation which are not the concern of the state.’
And the context of Germany was similar:
During the 1920s, it experienced violent uprisings, political assassinations, foreign invasion and a notorious Great Inflation. Then the Great Depression hit, causing immense suffering in Germany...For different reasons, both the era’s conservative governments and their socialist opponents primarily favoured austerity as a response to the crisis. ..The fascists also pledged to fight the Depression and contrasted its activism on behalf of the people’s welfare with the meekness and austerity of the government and the socialists. When, in January 1933, Hitler became chancellor, the Nazis quickly began work-creation and infrastructure programmes. They exhorted business to take on workers, and doled out credit. Germany’s economy rebounded and unemployment figures improved dramatically...By the end of the 1930s, the government was controlling decisions about economic production, investment, wages and prices. It included free higher education, family and child support, pensions, health insurance and an array of publically supported entertainment and vacation options. All spheres of life, economy included, had to be subordinated to the ‘national interest’
And here's the main point:
But for most Italians, Germans and other European fascists, the appeal was based not on racism, much less ethnic cleansing, but on the fascists’ ability to respond effectively to crises of capitalism when other political actors were not. Fascists insisted that states could and should control capitalism, that the state should and could promote social welfare, and that national communities needed to be cultivated.
For many Americans, the dream of the average joe (especially for those without a college education) with secure lifelong employment and a generous pension for himself and his children was at risk. They felt helpless as cheaper foreign products and outsourced jobs put their jobs and standard of living at risk. The issues are more complicated, of course; automation has replaced the need for some positions, and cheaper prices allow for spending on new products and services. And Trump's interventions had unintended consequences, e.g., as his Chinese tariffs led to fewer American farm exports, and he ended up redistributing tariff revenues from consumers to farmers.
There isn't anything comparable to the Italian black shirts or the German brown shirts, but Trump lionized local police, loathed state or municipality sanctuary policies for unauthorized migrants, and wanted to intervene during the post-Floyd protests, riots, arson, and lootings with an expanded federal police force. Many leftists will point to the Jan. 6 incursion of the Capitol where many Capitol police suffered minor injuries in confronting the protesters. Trump, who had earlier paid lip service to a peaceful protest, visibly dragged his feet in calling off his supporters and/or shoring up the outnumbered police with the National Guard. Trump similarly resisted distancing himself from extremist allies, merely slapped the wrists of aggressive supporters like the Boston brothers who pissed on a sleeping homeless Latino and beat him with a lead pipe. He notably admonished the police for being "too nice" to arrested suspects (e.g., rough rides) and promised to pay the legal fees for rallygoers who roughed up protesters at his rallies. The best you can say of Trump is that he was sending mixed messages.
You can clearly see his own spreading a Big Lie, like those underlying interwar fascism, in terms of spreading crackpot conspiracy theories over his failed reelection bid. A sizeable plurality or majority of Republicans seem to buy into the myth of a stolen election.
He had little interest in GOP austerity policies, quickly abandoning hard-earned sequester policies negotiated by the GOP against Obama in his eagerness to expand military spending, not to mention refusing to seek reform against senior entitlements his middle-class supporters felt they had earned, now beginning to drain their limited reserves as more longer-living Baby Boomers become eligible. He noted they won't expire in the short term of his President. In fact, he sought to do things like suspend or cancel payroll taxes, which would have hastened the date of reckoning.
Besides immigration, he had sought an infrastructure bill and sought to expand the social welfare net, e.g., paid family leave.
Trump also had a taste for the cult of personality (his self-serving pep rallies) . He frequently asserted "unlimited powers" of the Presidency, tried to transfer allocated funds (e.g., for his priority border fencing), and frequently abused the dubiously constitutional practice of executive orders. He openly admired authoritarian strongmen, boasted of his unique qualifications for the Presidency, speculated of negotiating a Bloomberg-like third term despite the 22nd Amendment. no doubt also looked at gimmicks like Putin's alliance with Medvedev (In fact, some Republicans have advanced the notion of naming Trump as Speaker of the House, a position in line for the Presidency.)
But I think it's hard to argue that Trump was ideological like the principals of interwar fascism. For one thing, he probably did more for deregulation than any recent President. He installed a free market head of the FCC in Ajit Pai, who blocked the Statist net neutrality toehold. He significantly cut corporate tax rates To be sure, Trump has done his share of corporate bashing as described above, not to mention Apple, which has refused a government backdoor through cellphone security. He was trying to cap prescription prices, allow prescription drug importation in middle-class support. And, yes, he's tried to force loose monetary policy, e.g., to ensure a strong economy for his reelection (in fact, discussing negative rates to match the EU). Along with his "Tariff Man" policies, nobody can serious argue Trump is a free market guy. But we see nothing like the nature and extent of economic intervention as Berman describes above.