The reason the mafia thrives in countries where it's hard to write legal contracts-- let's say some new parts of the former Soviet Union or some parts of Africa the reason the mafia thrives in those environments, is that it substitutes for the law and enforces both legal and illegal contracts.

黑恶势力在那些,书面协议不受保护国家不断壮大,比如前苏联新成员国 或者非洲,为什么黑恶势力在这些地方发展壮大,因为这是法律强制力的补充,它维系所有合同,不管是不是合法的

耶鲁公开课 - 博弈论课程节选

It was the new Mafia commerce in arms, drugs and above all people which concerned the delegates who were meeting in Palermo to sign the UN's first treaty on organised crime, which coincided with the opening of the new centre in Corleone.

BBC: Mafia - past and present

One such mammasantissima (ie, a very big shot), Bernardo Provenzano, who is still at large, is said to have told friends that this New Mafia must eschew bombs and shootings, and go back to backroom-deals with new friends in political circles just as in the old days.

ECONOMIST: Italy��s Mafia

In 2000, White led the prosecution of more than 100 people including members of all five New York Mafia families accused of strong-arming brokers and manipulating prices of penny stocks.

NPR: Obama Picks Former Prosecutor To Head SEC