I wouldn't say the most powerful, but Jimmy Burke pulled a lot of weight and kicked up plenty to the Vario crew. If he was Italian he'd have been made quite a while ago. He had his own crew at Robert's lounge and had all sorts of rackets, even though he's mostly known because of the Lufthansa heist (and Goodfellas)
Outside his own neighborhood he wasn't as powerful as you might think. And he had zero pull in trade unions or with anything remotely legitimate. In my opinion, to say "most powerful ever" would imply that he could pick up a phone and shut down a million dollar construction site, or order a wildcat strike. But it's like I always say, power is a relative term. And in Ozone Park Jimmy Burke was no one to be trifled with.
"I got news for you. If it wasn't for the toilet, there would be no books." --- George Costanza.
