Fifty-four years ago, one of the most suspicion-wracked and contentious international relationships (next to the U.S.’s with the Soviet Union) heated up when the United States and Cuba ended formal diplomatic ties and closed their embassies in Havana and Washington D.C., respectively.

The years following the break were marked by accusations of sabotage and attempted assassinations, proxy wars, and nuclear near-misses. That icy tension thawed a bit on Monday, July 20, 2015, if not completely, as both nations have opened their embassies once again. This news comes on the heels of renewed diplomatic talks and the lifting of embargoes and a decades-long travel ban.

The diplomatic dance has begun anew, and for those in the intelligence community, there are sure to be mixed feelings. Although access to the country has eased, lingering questions, concerns, and doubts, given our history, likely remain.

So after almost 55 years of trying to penetrate the inner workings of the tiny island that has proved to be a big policymaker nightmare, how might past events stack up for or against future U.S. intelligence operations in the region?

FILE - This Dec. 17, 2014 file photo shows a classic American car driving past the U.S. Interests Section buidling in Havana, Cuba. A half-century after Washington severed relations with Cuba, the seven-story mission is set to become a full-fledged embassy. The U.S. and Cuba announced on Dec. 17, 2014 they are re-establishing full diplomatic relations. (AP Photo/Desmond Boylan, File)
(Photo courtesy of AP/Desmond Boylan)

In the mid-1950s, Cuba began a relationship with the Soviet Union, creating an instant political rift with the United States, who to that point had enjoyed a cordial relationship with her tiny Caribbean neighbor. Havana had been the playground of many a famous name, from Ernest Hemingway (whose name now graces the ballroom in the Cuban former consulate/new-again embassy) to Hunter S. Thompson.

With her vintage cars, nightclubs and Spanish-style architecture, Cuba had long been a favored trek for movie star and spy, from British, to German, to the fledgling CIA. All of that changed in 1959, when a young communist revolutionary named Fidel Castro launched a successful and bloody coup that landed the island nation firmly in the USSR’s camp, and effectively closed the door to outside influence and observation.

For the CIA, outside of Moscow, Havana quickly became an intelligence focal point. Policymakers, most notably the Kennedy administration, wanted to know what was going on the island, and most importantly, what the Soviets had planned for their newfound little brother. Traditional HUMINT (human intelligence), while not yet to the “impossible” point, was proving more difficult as Castro’s forces rolled up both real and suspected agents, quickly imprisoning or executing them.

Some with anti-Castro leanings had fled the island in the initial stages of the revolution, but communications with those left behind needed to form a resistance army, if any, were scarce and soon, nonexistent. If the Castro regime was to be effectively resisted and hopefully toppled, the Agency would need to flex its covert action/covert influence muscle.