Hello, O_Pazzo, hope to see many thoughtful posts from you!

Labor (unions) has always been a great source of power for organized crime, in several ways:

1. Unions make members pay dues. Thus union treasuries are a great source of money for racketeers who dominate labor unions. Unions also administer pension funds, which contain enormous sums, often tax-exempt or -reduced. If you saw the movie, "Casino," you saw that the Teamsters Union Central States Pension Fund invested in a Las Vegas hotel/casino--and skimmed the profits for their Mafia bosses.
2. Unions have thousands of members who can constitute a voting bloc. If the union "leadership" (i.e., Mafia guys installed in leadership positions) endorses a particular political candidate, all the union members will be "urged" to vote for that candidate. When the candidate is elected, the candidate will owe a debt to the union leaders (i.e., Mafiosi, in corrupt unions) who endorsed him or her.
3. Unions can "shake down" bosses. Let's say you're a builder (contractor) putting up a big office building in a major city. All the construction workers are unionizied. They all have contracts with you. The contracts are as thick as a telephone book, and specify every working condition. Most of this is chicken-s**t. But, if the union bosses want to shake you down, they can call a "rulebook slowdown": they can insist, for example, that every truck entering the construction site be inspected for "safety" by their own members. They can insist that any overtime (which you may need to complete the job on time) be ordered two weeks or a month in advance. They can insist on investigating the union membership of every person who works on the site...it goes on and on. The net is: if you don't pay them off, they can shut you down or slow you up to the point that you'll never make a profit on that contract.