Exxon just won a critical legal battle to recover more than $1 billion from Cuba, and the Supreme Court's decision could open the floodgates for dozens of similar claims that have been stuck in legal limbo for years.

The court ruled 6-3 on Tuesday that Cuba's state-owned companies cannot use a legal shield called "sovereign immunity," which normally protects foreign governments from being sued in US courts, to block claims brought under a 1996 US law called the Helms-Burton Act. The decision reverses a lower court ruling from 2024 and sends Exxon's case back to a lower court to work out what Cuba actually owes.

The original seizure and the modern math

When Fidel Castro came to power in 1959, his government confiscated all of Exxon's Cuban oil and gas assets, including a refinery and service stations that had belonged to Exxon's corporate predecessor, Standard Oil. At the time, that property was valued at $70 million. Thanks to decades of accumulated interest and the possibility of enhanced damages under the Helms-Burton Act, Exxon's current claim has grown to more than $1 billion.

Cuba never paid for what it took. Its state-owned conglomerate, Corporación CIMEX, has continued to hold and profit from those assets ever since. Exxon's lawsuit, filed in 2019, accused CIMEX of unlawfully "trafficking" in the confiscated property, which is exactly the kind of claim the Helms-Burton Act was designed to enable.

Justice Brett Kavanaugh, writing for the six-justice conservative majority, was direct: the Helms-Burton Act "abrogates the sovereign immunity of Cuban agencies and instrumentalities." In other words, Cuba's companies cannot simply wave away American lawsuits by invoking Cuba's status as a foreign state.

Why this matters beyond Exxon

Exxon's case is just one of roughly 40 lawsuits filed under the Helms-Burton Act in 2019 and 2020. Most of those cases had stalled because lower courts kept throwing them out on procedural grounds. Tuesday's ruling clears the most significant obstacle those cases faced.

The Helms-Burton Act sat largely dormant for years because three consecutive presidents suspended its private lawsuit provision, worried about diplomatic friction with allies like Canada and Spain whose companies had invested in Cuba. President Trump lifted that suspension during his first term in 2019, and his current administration backed Exxon's appeal to the Supreme Court.

The stakes are not purely financial. The ruling lands at a moment of unusually sharp US-Cuba confrontation. The United States has effectively imposed a blockade on Cuba by threatening sanctions on countries that supply it with fuel, contributing to power outages and what Reuters described as Cuba's worst crisis in decades. On May 20, the US government brought murder charges against former Cuban President Raúl Castro. The Supreme Court decision adds another layer of legal and economic pressure.

The three liberal justices dissented, though the sources do not detail the specific grounds of their dissent.

The bigger picture

What the court has really done is validate a legal architecture designed to make Cuba pay for 1959 in 2026. Whether any of that money actually changes hands is a separate question. Cuba has no obligation to honor a US court judgment, and enforcing such a ruling against a foreign state with no significant US assets is genuinely hard. The practical path to collection would likely require Cuba to have assets or business relationships in US-reachable jurisdictions, which is precisely why the broader sanctions and blockade strategy matters: it shapes what leverage the US actually has.

For American companies that lost property in Cuba decades ago, Tuesday's ruling is the most favorable legal development in years. Whether it translates into actual recovery depends on political conditions that no court can guarantee.

The other Helms-Burton case decided this year went the opposite direction. On May 21, the court handed four American cruise lines a setback, allowing $440 million in combined judgments against them to stand in a case involving confiscated docks in Havana. That ruling is a reminder that the same law cuts in both directions.