Republican presidential candidate Donald Trump is no stranger to missteps that harm his campaign, and he may have just stumbled into a new one: he is being accused of knowingly violating the U.S. embargo on Cuba in the 1990s, an accusation that could cost him dearly in Florida, a vital swing state in the upcoming presidential election.

Newsweek just published a story alleging that Trump’s firm spend about $68,000 in exploring business possibilities in Cuba back in 1998, which would have been a violation of an embargo that had been in place since the Cold War.

While Trump acknowledged spending money to explore business ventures there through his spokeswoman Kellyanne Conway, she denied that he broke the law or committed a violation of the embargo.

But that might not be good enough for Cuban Americans in Florida, who are typically very anti-Fidel Castro. While Trump is already not expected to perform well among Latin Americans, even the few that do support him could switch sides in the hotly contested state because of this finding. Most Cuban-Americans are in favor of the embargo and protested Obama’s decision to lift the embargo recently. In addition, they tend to be high-turnout voters.

And clearly Trump wants their vote. He had a special meeting with them not long ago in an attempt to make inroads with them, so even he knows how important their vote is.

Ann Navarro, a conservative strategist who opposes Trump and is based in Florida, was quoted in the Washington Post as saying that it is “never a good thing when voters feel played and find out the candidate they are supporting is a hypocrite on an issue that carries the emotion that Cuba policy does.”