For most of the 20th century, New York was so full of mobsters, and was such a hotbed of mob activity, that it came to be known as "the volcano." Everyone knew the legends like Lucky Luciano, who organized the five ruling families and their associates into a crime "Commission" in 1931. Meanwhile, just about everything of value in the city was tied to the mob. Jumping beyond its Italian-American roots, the Mafia went mainstream once The Godfather hit theaters in 1972, as millions repeated lines like "I'll make him an offer he can't refuse" and "Luca Brasi sleeps with the fishes." Wiseguys grew to feel so comfortable - that is to say, invincible - that they started writing books about their crimes. That's when Rudolph Giuliani, a rising star in the Attorney-General's Office, stepped in. Utilizing a revolutionary but still misunderstood law from 1970 known as the Racketeer Influenced and Corrupt Organization Law, Giuliani orchestrated the highest-profile case against the Mafia in four decades. His goal, he boldly stated, was "to wipe out the five families." By convicting the heads and top advisers of the Gambino, Genovese, Colombo, Lucchese and Bonanno families, he nearly did. During a 20-year period starting in the early 1980s, federal prosecutors put close to 1,000 mafiosi behind bars. They did it using a clear formula - which would be copied almost immediately in Italy and, later, Japan and Hong Kong, and ultimately the UN - that included extensive electronic surveillance of suspects, an expansive witness protection program for snitches and government seizures of criminals' assets. But it all started with RICO. Under the law, a person or group who commits any two of dozens of crimes - any act or threat involving gambling, murder, kidnapping, arson, robbery, bribery, extortion, drug dealing, arms dealing, counterfeiting, embezzling, money laundering, etc. - within a 10-year period and as part of a pattern of crime can be charged with racketeering. In addition, sentences were increased, and the government was entitled to seize all ill-gotten gains and interest in any business gained through racketeering. To be sure, RICO was a formidable tool. But it was also complicated, required a totally different view of the nature of organized crime and had the potential for numerous far-reaching, unintended consequences. It went unapplied for a decade. "It took a long time for the prosecutors and the FBI to understand RICO. They were afraid to use it," recalls Selwyn Raab, who covered organized crime for The New York Times for nearly three decades and is the author of Five Families: The Rise, Decline, and Resurgence of America's Most Powerful Mafia Empires. "Before, it was very complicated to get a conviction. It was very difficult to pin a crime on a major figure because he never pulled a trigger, never demanded protection money himself. But RICO made it very difficult to even be a mobster. What was accomplished in New York proved how you could use RICO." G. Robert Blakey, who took the lead in drafting the RICO law and several other anti-crime laws, explains the idea that changed the way America fought organized crime. "Organized crime is usually centered around money and power, therefore it is distinguished in common law from murder, rape and robbery. Those are prosecuted one by one, not as part of a process," he says. "Now, the criminal code is a way of looking at the world and defining human action. And our law cared only about what you did, not who you were. That meant that when we tried crimes, we only wanted to look at individuals: one crime, committed one time, on one day. But everybody is a part of an organization... By selling money through loansharking or usury, criminals are in a business. They're not just drug dealers, for example, they're criminal entrepreneurs whose enterprise happens to be drugs. "Then think about this," Blakey continues. "They are committing the crimes as part of an organization. Some people are on the streets, some are in trials, some are in jail, etc. The organization is just like a merry-go-round, running those people through that cycle. So the impact of individual prosecutions is zero, because the wheel turns and there's always a new person out there on the street committing crimes. Which means that you have to think about the organization, not just the crimes." Once the justice system adapted to that kind of thinking, the Mafia's fortunes changed dramatically. Another important development was that the witness protection program, also set up in 1970, was put into high gear and became a very attractive option for mobsters looking for a way out. "That was terrific - one of Blakey's brilliant stratagems," says Raab. "It beat omerta [the Mafia code of silence]... because he understood that if people were threatened with going away for life, or even for 30 years, they might crack. Then you get them another identity." Thousands chose the refuge of the witness protection program. And what turncoats didn't provide for the prosecution, extraordinary levels of wiretaps and other methods of electronic surveillance did. The magic formula was working. "Not long ago," says Blakey, now a law professor at Notre Dame, "one of my students and I put together a master list of everybody who has been identified by the Justice Department or the FBI as a member of the mob. We looked for name, date of birth, when and how he died. "Then we looked up indictments, prosecutions and sentences. We had all the data separated into categories - prosecutions and sentences before RICO, expanded wiretaps and witness protection, and after them. What this did was gather the empirical data that confirmed what everybody already knew: [This combination] has been a very powerful tool in prosecuting organized crime." From the beginning, the effects were sudden. Convictions came so quickly that, in 1987, Giuliani predicted the American Mafia would cease to be a major threat in just another decade. Blakey, slightly more cautious, said, "It's the twilight of the mob. It's not dark yet for them, but the sun is going down." That's certainly the way things lookedâ€¦ for a while. "At one point," says Raab, "the FBI declared two families - the Bonannos and the Colombos - dead or moribund, and had taken their squads off them. But 10 years later, the Bonannos had come back to life." What happened, essentially, was that the September 11 attacks stopped everything, forcing America to shift its energies toward terrorism like never before. "For about 20 years, the FBI had two missions: counter-espionage and the Mafia," says Raab. "But from 2001, the FBI reordered its priorities. In New York, until about 2000, it had about 450-500 agents and investigators working full-time on organized crime. Now, it's down to less than 100, and the police are doing practically nothing. It's given a breathing spell to the Mafia." The mob, which had proven to be both highly adaptive and highly resilient, had been crippled. But it began to regenerate as soon as the pressure abated. That's why, in Raab's estimation, fighting the Mafia is a constant battle. "Look, the FBI got a game plan together on how to do this," he says. "But you need a lot of people. You've got to do it full-time. And you've got to be fully committed." Otherwise, he concludes, the mob "is like Dracula. He's dead, and he's in his coffin. But if you're not careful, he's going to rise every sunset. If there's darkness, he'll thrive... unless you put a stake through his heart."