President Obama’s decision to reestablish diplomatic relations and “defang” the U.S. embargo of Cuba has split the potential 2016 Republican field. Sen. Rand Paul is in favor of Obama’s move, while Jeb Bush, the former Florida governor, and Sen. Marco Rubio, also of Florida, are against it. Rubio has gone so far as to say Paul “has no idea what he’s talking about” on the issue.

Bush and Rubio are making the smart political play here.

Most Americans aren’t going to base their vote on U.S.-Cuban relations. The issue doesn’t rank anywhere on a list of most important problems for Americans. For political purposes, Obama’s decision probably only matters among those who are most passionate on the issue: mainly Cuban-Americans.

As I pointed out previously, the issue is pretty much a wash among Cuban-Americans in the general election. According to polling from Florida International University, Cuban-Americans in South Florida (where most Cuban-Americans live) are split about evenly on the embargo.

Among Cuban-American Republicans, however, support for the embargo is highest.

In FIU’s 2008 survey — which had similar overall results to their 2014 poll — John McCain supporters favored the embargo 73 percent to 27 percent. Obama voters were almost exactly the opposite: 70 percent against and 30 percent for. The embargo’s biggest supporters are older Cuban-Americans, who are quite Republican-leaning, compared to younger Cuban-Americans, who are quite Democratic-leaning.

These Cuban-American Republicans could easily swing a relatively close Florida Republican primary. Cuban-Americans make up a sizable 8 percent of the primary vote in Florida, which is greater than the 6 percent Cuban-Americans make up in the general election. More importantly, though, Cuban-Americans have voted in a bloc in the past two presidential primaries.

In 2008, Cuban-American voters in Florida cast 54 percent of their ballots for John McCain compared to just 32 percent for Rudy Giuliani. McCain actually lost among white voters to his nearest rival, Mitt Romney, but was able to win the primary by 5 percentage points primarily because Romney won only 9 percent of the Cuban-American vote.

In 2012, Cuban-American voters switched their allegiance to Romney. He won 57 percent of the Cuban-American vote in the primary, while Newt Gingrich won only 31 percent. Romney’s best county in the state, like McCain’s, was Miami-Dade, which is home to a large Cuban-American community.

What made Cuban-Americans switch support from McCain in 2008 to Romney in 2012? One constant between the two candidates was whom the local Cuban-American politicians endorsed. In 2008, Reps. Ileana Ros-Lehtinen, Lincoln Diaz-Balart and Mario Diaz-Balart endorsed McCain early in the campaign. In 2012, they decided to back Romney.

Now, Ros-Lehtinen and Mario Diaz-Balart (Lincoln, his brother, is retired) are very much against Obama’s Cuba actions. Diaz-Balart called him the “appeaser-in-chief,” while Ros-Lehtinen called his acts “immoral” and “illegal.” It’s unlikely that they would endorse anybody who supported Obama’s outreach efforts.

Paul wasn’t a favorite to win the Cuban-American vote in a Florida primary against Bush and Rubio. But with his support of restoring U.S. relations, Paul has almost certainly lost that community. If a candidate wants to win Cuban-American voters in a Republican primary, he can’t be backing Obama on Cuba.