Given how broadly the Republican convention this year was primarily focused on bolstering the party’s nominee for president, there were a remarkable number of speakers who were targeted specifically at relatively small voting demographics. Perhaps none was more specifically focused than businessman Maximo Alvarez, who spoke on the convention’s first night.

Alvarez immigrated to the United States from Cuba. His argument centered on the differences between the two countries in which he’d lived and on what he presented as former vice president Joe Biden’s socialist policies

“When I watch the news in Seattle, Chicago, Portland and other cities, when I see the history being rewritten, when I hear the promises, I hear echoes of the former life I never wanted to hear again,” he said. “I see shadows I thought I had outrun.”

This message echoes the case being made by President Trump’s campaign, a case that is generally dubious in its efforts to reshape Biden’s record. But Alvarez wasn’t there to convince blue-collar workers in Michigan. He was there, it’s safe to say, to bolster Trump’s position with Cuban Americans in Florida.

Nationally, Biden maintains a big advantage among Hispanic voters relative to 2016 exit polling. A Washington Post average of recent polls shows that he’s faring almost as well as Hillary Clinton did with that group four years ago. In Arizona, he’s outperforming Clinton — a good sign for his candidacy. But in Florida, the picture is starker for the Democrat: His lead over Trump is only in the low double-digits.

Why? Several recent polls have offered a hint: the density of the more-heavily Republican Cuban vote.

The differences between Cuban American and other Hispanic voters was obvious in 2016 exit polls. About 3 in 8 Hispanic voters in the state were Cuban that year, and they preferred Trump by 13 points. Non-Cuban Hispanics preferred Clinton by 45 points, more in line with the national figure.

Several recent polls have reflected similar differences: Cuban American voters more strongly support Trump than do Hispanic voters overall. Hence the problem for Biden. About three-quarters of Cuban immigrants to the United States live in the electoral-vote heavy swing state of Florida.

The same phenomenon is visible at a county level nationally.

There’s a loose correlation between the density of the Hispanic population in a county and how the county voted in 2016. Two heavily Hispanic counties stand out here, Los Angeles and Miami-Dade. The former was more heavily supportive of Clinton despite being less heavily Hispanic.

Miami-Dade also has a large Cuban American population — the largest in the country.

Comparing the density of the Cuban population among a county’s Hispanic population, the results-vs.-density chart reverses. Setting aside places with small Hispanic populations (such as Wheeler County, Neb.), a few counties stand out. A number are in Florida.

One of the interesting trends in Cuban American politics has been the difference in partisan identity between older and younger Cuban Americans. When then-President Barack Obama began an effort to normalize relations with Cuba in 2014, we noted data from Pew Research Center showing that while Cuban Americans overall had become more Democratic, it was younger Cuban Americans (fewer of whom are immigrants) who were more likely to be Democrats.

Those data haven’t been updated since 2013, but the pattern isn’t unexpected. Vietnamese immigrants in California, for example, are often more heavily Republican, in part because Republican politicians in the United States like Ronald Reagan held a more hard-line position against communist and socialist states.

That’s the sentiment that Alvarez was meant to bolster. There are about 1 million Cuban Americans in Miami-Dade County, according to the Census Bureau — in a state that Trump won in 2016 by 113,000 votes.

If Biden does substantially worse with that group in 2020, it becomes less likely that he’ll turn the state blue.