The Commission was a group of heads of Mafia families that met regularly to work out inter-family problems. The Commission was designed to save the mob from autocratic rule by dictatorial bosses and internecine warfare. It worked for a while, but its main effect was to increase Luciano’s power. Luciano became so powerful, in fact, that he was the main target of New York D.A. Thomas Dewey, who built his political reputation by prosecuting top mobsters.

In 1936 Dewey successfully convicted Luciano of controlling prostitution in New York. At the end of World War II, Luciano was released from prison and deported to Italy.

In 1946 Luciano traveled to Cuba in an effort to reassert his power over the American mob. All of the most prominent underworld leaders traveled to pay their respects to Luciano at the famed "Havana Conference." It looked as if Luciano would be able to hang onto his position and rule the mob from Havana. Sinatra made at least two trips to Havana to meet Luciano. One trip was over Christmas 1946. Sinatra performed on Christmas Eve at a party held in his honor by Luciano. This party came during a break in a meeting that decided the fate of Siegel, who was killed a few months later. The second trip, over a four-day weekend in February 1947 is documented in Sinatra’s FBI file. He travelled to Havana with Joseph and Rocco Fischetti. They stayed at the Hotel Nacional and all three met with Luciano on more than one occasion.

This trip was widely reported in the media and it caused Sinatra problems the rest of his life – both with the public and the underworld. That trip would later lead to allegations that Sinatra delivered $2 million in cash to Luciano.

Joseph "Doc" Stacher, who ran Meyer Lansky’s operation in New Jersey at the time and later ran the Sand’s Hotel, remembered the Havana meeting years later in an interview quoted in Kitty Kelley’s His Way: "The Italians among us were all very proud of Frank. They always told me they had spent a lot of money helping him in his career ever since he was in Tommy Dorsey’s band. Lucky Luciano was very fond of Frank’s singing. Frankie flew into Havana with the Fischettis, with whom he was very friendly, but of course, our meeting had nothing to do with hearing him croon…Everyone brought envelopes of money for Luciano …But more important, they came to pay allegiance to him." It is likely that Sinatra also gave an envelope of cash to Luciano, but it is far-fetched that he carried $2 million in his briefcase for him, as it was later charged. As Sinatra said in his 1981 NSGC hearing, "Show me a briefcase that will hold $2 million in cash and I’ll give you the money." Shortly after the February meeting Robert Ruark, a New York columnist, wrote an article about Sinatra’s visit to Luciano. The U.S. government put pressure on Cuba to deport Luciano to Italy. Many mobsters thought that it was Sinatra’s bragging about meeting Luciano that led to his deportation. This led to Sinatra’s reputation as a "big mouth".

Luciano knew better. According to organized-crime historian and writer Allan May, Luciano believed that Vito Genovese had informed on him by telling Harry Anslinger of the Narcotics Bureau that Luciano was in Havana. (See "Havana Conference - 1946", by Allan May.) Sinatra and Hank Sanicola later visited Luciano in Naples, Italy, where Sinatra presented him with a gold cigarette case engraved: "To my dear pal Charlie, from his friend Frank." The cigarette case and a piece of paper bearing Sinatra’s unlisted telephone number were found on Luciano when Italian police searched him in 1949.