After Fidel Castro’s authoritarian regime took control of Cuba in 1959, the US responded in 1960 by imposing a trade embargo – a prohibition against commercial, financial and economic dealings with Cuba enforced over time by a minimum of six statutes. In 1961, the US severed diplomatic relations with Cuba after the government transitioned to a Communist system and commandeered US property located within the country. Regardless of the embargo, the US continued to supply food to Cuba as well as permit humanitarian support for political prisoners, human rights and pro-democracy groups.

The US Central Intelligence Agency attempted to assassinate Castro on eight separate occasions between 1960 and 1965, as confirmed [PDF] by a US Senate Intelligence Committee hearing in 1975. Following these attempts, between 1968 and 1972, approximately 75 US flights were hijacked by Cuban exiles and diverted to the island.

In 1980, US President Jimmy Carter attempted to normalize relations with Cuba without completely lifting the embargo or reinstating diplomatic relations. He established open interest sectors in each country’s capital, and welcomed Cuban immigrants to the US. During a period of mass emigration from Cuba, known as the Mariel Boatlift, 125,000 refugees landed in the US. Most of the refugees were either prisoners or mentally ill patients.

Relations between the two countries immediately soured and came to a head in 1996 when Cuban aircraft shot down two civilian planes in international airspace, killing 3 US citizens and a US resident. US President Bill Clinton signed the Cuban Liberty and Democratic Solidarity Act (also known as the LIBERTAD Act or the Helms-Burton Act) [PDF], which codified the trade embargo and declared a formal policy promoting a democratic Cuba.

The UN General Assembly formally adopted a resolution requesting that the US drop its embargo against Cuba in October 2008. Democratic Congressman William Delahunt of Massachusetts responded in February 2009 by introducing legislation that would permit US travel to Cuba. Although the bill was eventually signed by 179 co-sponsors, it has remained in limbo at the House Committee on Foreign Affairs since Delahunt introduced the bill in 2009. The Obama Administration later suggested that it might lift travel restrictions in April 2009.

President Obama formally eased travel restrictions and prohibitions on international money transfers between Cuban and Cuban-American families later in April 2009. In September 2009, the US Treasury helped facilitate travel by loosening telecommunications restrictions between the two countries. President Obama further loosened travel restrictions in 2011, allowing religious and educational programs to visit Cuba.

While the federal government was in the process of lifting travel and financial restrictions between Cuba and the US, the state of Florida signed a law precluding state contracts with businesses that perform work in Cuba. The Brazilian construction conglomerate, Odebrecht Construction, Inc., filed suit against the state in June 2012, stating this ban violated the Supremecy Clause and savings clause of the US Constitution. The US District Court for the Southern District of Florida issued a temporary injunction against the law in June 2012. The US Court of Appeals for the Eleventh Circuit upheld the injunction in May 2013, stating the law indeed violated the Supremacy Clause, as the Florida law contradicted the current federal regime.

On December 17, 2014, President Obama instructed US Secretary of State John Kerry to reestablish diplomatic ties with Cuba and announced a new policy permitting travel and trade between the two countries.