President Donald Trump’s move to let U.S. citizens file lawsuits over property confiscated in Cuba during the 1959 revolution angered European allies who vowed to challenge the reversal of more than two decades of policy.

“Sadly, Cuba’s most prominent export these days is not cigars or rum, it is oppression,” Secretary of State Michael Pompeo said in announcing the turnaround on Wednesday. “Detente with the regime has failed. Cozying up to Cuban dictators will always be a black mark on this great nation’s long record of defending human rights.”

On May 2 the U.S. will begin enforcing a provision of a 1996 law known as the Helms-Burton Act that allows Cubans who fled Fidel Castro’s regime to sue companies that have used their former property on the island. Like his predecessors, Trump had previously waived the provision, Title III, because enforcing it could result in a flood of litigation against foreign companies.

The European Union, the biggest foreign investor in Cuba, threatened action before the World Trade Organization or other possible retaliation over Trump’s Cuba move.

“The European Union reiterates its strong opposition to the extraterritorial application of unilateral restrictive measures which it considers contrary to international law,” Alexander Winterstein, spokesman for the bloc’s executive arm, told reporters in Brussels on Wednesday. “Let me stress that the EU is ready to protect European interests, including European investments and the economic activities of EU individuals and entities in their relations with Cuba if these were to be affected.”

Reversing Obama

It’s part of Trump’s broader push to reverse moves by his predecessor Barack Obama that eased the U.S. trade embargo with Cuba. He also wants to punish Cuba over its support for Venezuelan President Nicolas Maduro, who has managed to stay in power despite massive U.S. sanctions and a move by the Trump administration to recognize Juan Guaido as the country’s legitimate leader.

The State Department said no exemptions will be granted from the right to sue.

A group that advocates ending the trade embargo on Cuba emphasized in a statement Tuesday that U.S. companies also will be affected. “This decision punishes the Cuban people and American companies—companies who were given permission by the U.S. government to do business and are now having the rug pulled from underneath them,” said James Williams, President of Engage Cuba.

White House National Security Adviser John Bolton planned to boast of Trump’s move in a speech in Miami on Wednesday criticizing governments in Cuba, Venezuela and Nicaragua that he has branded a “troika of tyranny.”

Florida Politics

Bolton’s appearance at a commemoration of the failed Bay of Pigs invasion of Cuba in 1961 has political implications for Trump’s re-election campaign.

Latinos are about a quarter of Florida’s electorate and Cuban-Americans, who have traditionally leaned Republican, are the biggest single group. But their political power in the state has eroded in recent decades as immigrants from Puerto Rico and other areas of Latin America have arrived, and as younger Cuban-Americans shift to the Democratic Party, according to a Pew Research Center study.

Earlier this month, Trump blocked an agreement under which Cuban baseball players returned some of their signing bonus to the country’s baseball federation. The deal, signed with the Major League Baseball Association, had been meant to allow Cubans to travel to the U.S. freely rather than having to defect and find their way to American soil on their own.

Tens of Billions

The State Department has said that some of the biggest claims under the 1996 Helms-Burton law include companies such as Office Depot Inc., Exxon Mobil Corp. and Coca Cola Co. Many may not bring suits because they would effectively be targeting clients overseas.

Kimberly Breier, assistant secretary of state for Western Hemisphere affairs told reporters Wednesday that there are 6,000 claims already on record and potentially as many as 200,000 with a value in the tens of billions dollars.

While lawsuits would take years to wind their way through the legal system, the impact is likely to be felt almost immediately, said Peter Harrell, a fellow at the Center for New American Security, a Washington-based research group

“It’s going to be pretty long road ahead to actually winning any judgments but the Trump administration will get what it wants out of this because you’re going to see a number of European companies decide the risk isn’t worth it,” Harrell said.

Europeans are not alone in objecting to Trump’s move.

Canadian Foreign Minister Chrystia Freeland discussed Helms-Burton with Pompeo on the sidelines of the NATO meeting in Washington at the beginning of April. She told her American counterpart that her government, led by Prime Minister Justin Trudeau, “will defend the interests of Canadians conducting legitimate trade and investment with Cuba, if the United States enforces Title III,” according to a readout from her office.

Canadian miner Sherritt International Corp., which has been mining nickel in eastern Cuba since 1994 and also has oil-and-gas operations near Havana, declined to comment in advance of the official announcement.