It has been a persistent ghost in the machine in the US election: Latin America. Haunting the red corner are the 11m undocumented migrants, mostly Hispanic, that Donald Trump wants to deport; the wall the Republican nominee will build; and Gonzalo Curiel, the unfair “Mexican judge” — born in Indiana — who ruled against him. The spectres in the blue corner are Hillary Clinton’s belief that “no region is more important to US prosperity and security”; and, less benevolently, the fleeing Central American minors that the Democratic nominee once advocated should be sent home.

It has long been a home truth that the Hispanic vote — 12 per cent of the US electorate — has a good chance of determining the election result. That is especially so this year. In addition to the central issue of immigration, the Hispanic vote is laden with millennials — a liberal-leaning generation that came of age at the turn of the century and, while anti-establishment, tends to reject Mr Trump. Moreover, for their parents and grandparents, Mr Trump is the kind of candidate who may well recall the reasons they emigrated in the first place.

When Mr Trump swaggers with all the braggadocio summoned by some strange telluric process from the majestic prairies of . . . well, Queens, New York, he seems to have stepped out of a dread passage of Latin American history. It is sometimes said that he shares traits with populist strongmen such as the Dominican Republic’s Rafael Trujillo, or Argentina’s Domingo Perón and Carlos Menem — and then some.

There is the obsession with virility and often notable hairstyles, such as Mr Menem’s sideburns. There is the narcissism and self-aggrandising nationalism: Mexican independence hero General Antonio López de Santa Anna staged a state funeral for his amputated leg. There is also the authoritarianism: Hugo Chávez of Venezuela, another shrewd showman, fired ministers on a whim in his reality television show too.

It is ironic that Latin America appears to be rejecting populist leaders just as Europe and the US may embrace them. The region has undergone momentous change in the past year. Argentines have chosen a business-friendly centrist, Mauricio Macri, as their president. Brazil has channelled popular anger over state-sanctioned corruption into the pursuit of impeachment for Dilma Rousseff, a process that culminates after the Rio Olympics. Socialist Venezuela is on the brink of collapse. Only in Nicaragua, Bolivia and Ecuador, where Rafael Correa is a rare foreign leader who backs Mr Trump, do the populists endure.

This is where a direct line may exist between Latin America’s latest swing in its political pendulum and how Hispanics may determine the US election result. Typically, they share other voters’ main concerns: the economy, terrorism and healthcare. They also traditionally vote for the Democrats. A big difference this year is that millennials make up 44 per cent of the bloc.

This group is defined more by demography than vague notions of shared ethnicity (most say they do not need to speak Spanish to be Hispanic). Many are the children of immigrants. More importantly, suggests Professor Roberto Suro of the University of Southern California, they see themselves as Americans, proud of the US emphasis on the rule of law where claims and principles, such as citizenship, are adjudicated by an impartial state rather than an erratic leader, such as Mr Trump.

Many of their parents, meanwhile, have suffered the populist show before. One oft-cited reason for the rise of US populism is growing inequality, another traditional Latin American woe. Indeed, Omar Encarnación, professor of political studies at Bard College, highlights the US Gini index, a widely used measure of inequality, which stands in the range of 40 to 45. This is just below 40 to 50 in Latin America but well ahead of Canada or Europe at about 30.

Rage against the elites is a second reason given for the rise of US populism. Again, Latin America has form and intellectual heft here. Ernesto Laclau, a post-everything Argentine political theorist, even made a career explaining and advocating it. An important intellectual influence on the leftwing parties of Spain’s Podemos and Syriza in Greece, Laclau, who died two years ago, argued populism was the best post-Marxist alternative for pro­letariats abandoned by elites who had entrenched privilege, betrayed liberal positions, and so deformed institutions.

That may be true enough: populists are not born in a vacuum. They meet a need. Yet recent history reminds us that betrayal of promises is almost a definition of populism. Classically, that is done through deficit-spending financed by central bank money-printing, which generates runaway inflation — a view that may need updating in these days of quantitative easing.

All this may sound very familiar to US voters, wherever they stand on the political spectrum. It may also be familiar to Mrs Clinton and Mr Trump. Both know Latin America well: Mrs Clinton from her time as secretary of state; Mr Trump from the hotels and resorts licensed under his gold-lettered franchise: one, in Panama, restructured under Chapter 11 bankruptcy; another, in Mexico, went bust before it was built.

It is certainly familiar to Hispanics, about 70 per cent of whom are regularly shown by polls to favour voting for Mrs Clinton versus about 20 per cent for Mr Trump. From painful personal experience, many have learnt the difference between a champ and a chump.

johnpaul.rathbone@ft.com

This article has been corrected to reflect that Judge Curiel was born in Indiana not Iowa as originally stated.