I think that most families were at the height of their power by the mid to late 50's and early 60's, around the time of Appalachian and the Kefauver hearings. After that the government and law enforcement, at least publicly, could no longer look away and tell the public that there was no problem with organized crime.

As for the Genovese, I think that the height of their power was sometime from the late 30's through the early 60's, in other words the end of Lucian's reign through Costello's reign and the beginning of Genovese's time at the top. That was when their power was the most expansive, when family members like Costello, Alo, Tourine, Trigger Mike Coppola, and Catena had holdings all over the country and internationally as well. That was also the period when their associates like Lansky, Zwillman, Stacher and Nesline were at their peak. The Genovese were the biggest, most powerful family in NYC and NJ, they probably were the most active family in South Florida through Lansky, Coppola and others, and were arguably the most active family in Cuba as well. They were either the most invested or the second most invested family in Vegas during that time, and they were active in New Orleans and Newport, Kentucky through Trigger Mike. Stacher and Siegel were active on the West Coast with gambling and the movie studios as was Zwillman, they were active in other areas of the Caribbean as well as Europe, they already had crews in Springfield, Mass and Connecticut, and they were already strong in the Teamsters through Tony Provenzano and others. They also had Nesline in Washington, DC. They also had Morris Levy in the record industry and they had a big stake in the William Morris agency in the entertainment filed. During that time I think that the only family that was even close was Chicago.

The Genovese were never second behind the Gambinos in power until maybe the late 60's, and even then I think that that is doubtful. The Gambinos may have had a few more men, but they never had as wide an array of rackets as the Genovese. They were only minimally involved in Vegas and were not as involved in Cuba, they were never involved in New Orleans or Newport. They also weren't as strong in Florida, New England or NJ, and they were not nearly as powerful within the Teamsters. They never had the strong base of associates that the Genovese had as Lansky, Zwillman, Stacher and Nesline were powers in their own right. The only area where they had any advantage over the Genovese was in drug trafficking, but I believe that they did not get heavily involved in drugs until the late 60's if I recall correctly.

The only time that you could argue that the Gambinos were stronger was the period from the late 60's, when Vito Genovese died, to the early 80's. However, I think that that is more of a media creation, as Carlo Gambino had become the public face of organized crime through the media during that time, the stereotypical godfather. Just because the Genovese used a power sharing agreement and kept the actual identity of their boss hidden did not mean that the family lost any power. Until the Chin rose to the top in the early 80's bosses/ front bosses like Catena, Tieri and Salerno may have been less interested in Commission politics than Carlo Gambino and he may have been the most powerful boss on the Commission,. However, just because he was the biggest boss on the Commission does not mean that his family was the most powerful, kind of like Massino being arguably the biggest boss in the late 90's did not make the Bonannos the strongest family in NYC. The Genovese were still making more money and had more big earners than the Gambinos, even during that time period. If nothing else, just remember Carlo Gambino needed the Genovese family's namesake to make help make him boss.