Is Donald Trump a fascist? The question is usually posed as an insult rather than as a serious inquiry. A common response is that “he is not as bad as Hitler”, but this rather dodges the issue. Hitler was one hideous exponent of fascism, which comes in different flavours but he was by no means the only one.

The answer is that fascist leaders and fascism in the 1920s and 1930s were similar in many respects to Trump and Trumpism. But they had additional toxic characteristics, born out of a different era and a historic experience different from the United States.

What are the most important features of fascism? They include ultra-nationalism and authoritarianism; the demonisation and persecution of minorities; a cult of the leader; a demagogic appeal to the “ignored” masses and against a “treacherous” establishment; contempt for parliamentary institutions; disregard for the law while standing on a law and order platform; control of the media and the crushing of criticism; slogans promising everything to everybody; a promotion of force as a means to an end leading to violence, militarism and war.

The list could go on to include less significant traits such as a liking for public displays of strength and popularity at rallies and parades; a liking also for gigantic building projects as the physical embodiment of power.

Hitler and Mussolini ticked all these boxes and Trump ticks most of them, though with some important exceptions. German and Italian fascism was characterised above all else by aggressive and ultimately disastrous wars. Trump, on the contrary, is a genuine “isolationist” who has not started a single war in the two-and-a-half years he has been in the White House.

It is not that Trump abjures force, but he prefers it to be commercial and economic rather than military, and he is deploying it against numerous countries from China to Mexico and Iran. As a strategy this is astute, avoiding the bear traps that American military intervention fell into in Iraq and Afghanistan. It is an approach which weakens the targeted state economically, but it does not produce decisive victories or unconditional surrenders.

It is a policy more dangerous than it looks: Trump may not want a war, but the same is not true of Mike Pompeo, his secretary of state, or his national security adviser John Bolton. And it is even less true of US allies like Saudi Arabia and the United Arab Emirates, who have been pushing Washington towards war with Iran long before Crown Prince Mohammed bin Salman took control in Riyadh in 2015.

Trump’s aversion to military intervention jibes with these other influences, but it is erratic because it depends on the latest tweet from the White House. A weakness, not just of fascist leaders but of all dictatorial regimes, is their exaggerated dependence on the decisions of a single individual with God-like confidence in their own judgement. Nothing can be decided without their fiat and they must never be proved wrong or be seen to fail.

Trump has modes of operating rather than sustained policies that are consequently shallow and confused. One ambassador in Washington confides privately that he has successfully engaged with the most senior officials in the administration, but this was not doing him a lot of good because they had no idea of what was happening. The result of this Louis XIV approach to government is institutionalised muddle: Trump may not want a war in the Middle East but he could very easily blunder into one.

Of course, Trump is not alone in this: populist nationalist authoritarian leaders on the rise all over the world win and hold power in ways very similar to the fascists of the inter-war period. What is there in these two eras almost a century apart that would explain this common political trajectory?

Fears and hatreds born out of the First World War, the Russian Revolution and the Great Depression propelled the fascists towards power. When old allegiances and beliefs were shattered and discredited, people naturally looked to new creeds and saviours. “The more pathological the situation the less important is the intrinsic worth of the idol,” wrote the great British historian Lewis Namier in 1947. “His feet may be of clay and his face may be blank: it is the frenzy of the worshippers which imparts to him meaning and power.”

Is the same thing happening again? Fascism was the product of a cataclysmic period in the first half of the 20th century that is very different from today. The US failed to get its way in wars in Iraq and Afghanistan but these were small-scale conflicts in no way comparable to the First World War. The recession that followed the 2008 crash was a blip compared to the Thirties.

Many of the better off reassure themselves with such thoughts. But they underestimate the destructiveness of de-industrialisation and technological change for great numbers across the globe. Inequality has vastly increased. Economies expand, but the benefits are skewed towards the wealthy. Metropolitan centres plugged into the global economy flourished, but not their periphery.

The distinction between winners and losers varies from country to country but governments everywhere underestimated the unhappiness caused by social and economic upheaval. Beneficiaries of the status quo invariably downplay the significance of fault lines that populists are swift to identify and exploit.

Philip Hammond, the British chancellor of the exchequer, contemptuously dismisses claims by the UN that great number of people in Britain were living in “dire poverty” and saying that, in so far as deprivation existed, the government was acting effectively to address the problem. The new wave of Trump-like leaders springing up all over the globe do not have to do very much to do better than this.

Such overconfidence on the part of the powers-that-be is becoming rarer. Democrats who had convinced themselves that Trumpism would be exposed and discredited as a conspiracy wished on America by the dark powers in the Kremlin have seen their fantasy evaporate.

But there is probably worse to come: experience shows that populist authoritarian nationalism – what Namier called “Caesarian democracy” – is not a static phenomenon. It may not begin with all the fascist characterisation listed above, but its trajectory is always in their direction. Regimes become more nationalistic, authoritarian, demagogic, shifting from intolerance of criticism or opposition to a determination to extinguish it entirely.

A case study of this process is Turkey, where President Recep Tayyip Erdogan is reinforcing his one-man rule by overturning an opposition victory in the election to choose the mayor of Istanbul. Many Americans deny that the same process is happening in the US, but they tend to be the same people who did not believe that Trump could be elected in the first place.