Firstly it by taking over a union, they can control the workers in said union which in turn allows them to use these workers as a form of leverage against those who have hired union members. read more
Unions in countries outside of America have had confirmed involvement in organized crime. Sanitation workers in Naples, Italy for example. Organized crime may have interest in unions because of the power they have over workers and industry, just as they would benefit from corrupting politicians and police. read more