When Donald Trump talks about the criminal indictments against him, he often compares his treatment to that of a political dissident in an authoritarian regime.

In the last year, he has provoked controversy by describing the prosecutions as a “Stalinist Russia horror show” and himself as like Nelson Mandela, who spent 27 years imprisoned in South Africa.

But speaking at a rally in Hialeah, Florida, on Wednesday, the former president chose a different comparison.

“Just like the Cuban regime, the Biden regime is trying to put their political opponent in jail,” Mr Trump told thousands of supporters assembled in a sports stadium. “We are not the ones endangering American democracy, we are the ones saving American democracy.”

His choice of a Latin American analogy was deliberate and designed to appeal to Latino voters who have become a key battleground demographic in the race for the White House.

In Florida, Latino voters are thought to be partly driving the state’s shift towards the Republicans that saw the party pick up a supermajority in state legislative elections last year.

Miami-Dade county, where Mr Trump’s rally took place, is a historic Democrat stronghold home to 1.5 million Latinos. In the 2016 presidential race, Hillary Clinton beat Mr Trump there by 30 points, but in 2020 the Democrats’ margin was reduced to 7 per cent.

Nationally, there is also reason to think Latino voters are no longer as safe for the Democrats as they once were. Between 2016 and 2020, the share of Latino voters choosing the Republicans in House elections increased from 28 per cent to 38 per cent.

A recent report by the Brookings Institute, a think tank, argued that although Mr Trump’s platform was appealing to some Latino voters in 2020 who were concerned about the economy, an expected fall in inflation is likely to reduce his appeal.

The report’s authors said Mr Trump generated around 10 per cent more Latino votes in 2020 than would normally choose a Republican candidate, but his support was fuelled by the group’s disproportionate concern about the economy and his promise to immediately lift Covid lockdown measures.

However, recent polling suggests that the group is one of several demographics that are usually aligned with Democrats where Joe Biden faces losing support in 2024.

A survey for the New York Times found that the president’s lead over Mr Trump among Hispanics is in single digits in six swing states of Arizona, Georgia, Michigan, Nevada, Pennsylvania and Wisconsin. A “normal” result for a Democratic candidate would be a lead of more than 30 points.

One of the states, Nevada, has a high Latino population and voted for the Democrats in 2016 and 2020 by a margin of around 2.4 per cent. A collapse in support among Hispanic voters could be enough to swing the state next year.

In response, the Biden campaign has launched two new adverts targeting Latino voters, selling his record on supporting Hispanic small businesses, opposing Latin American dictatorships and giving protected status to Venezuelan immigrants. Mr Trump’s campaign says the president is in “a full-blown crisis”.

Far from being an anomaly, Florida’s Miami-Dade county may actually represent a wider shift away from Mr Biden’s party that would provide a boost for Mr Trump and other Republican contenders next year.

The Latino vote is especially important in 2024 because the group is growing as a proportion of the electorate. The Pew Research Centre, a Washington think tank, estimates that one million Hispanic voters will turn 18 every two years for the next two decades.

A failure to hold onto Hispanic votes poses a major risk not just for Mr Biden, but for his party in years to come.