Although the Mafia has gotten a reputation as am efficient, ruthless killing machine, that perception, like so many others, is founded more on myth than reality. While it did achieve a significant amount of underworld power, the idea that Mafioso's achieved power by slaughtering dozens of people is mostly unfounded. The Mafia was run as a business, and achieved prosperity the same way your average business does. (The infamous Saint Valentine's Day Massacre was the most notorious example of Mafia violence, and only seven people were killed. In present day Chicago, that wouldn't even make the front page.)
This normalcy in the crime business takes a bit of the romance away from the Mafia of crime novels and movies. After all, if the real-life Godfather is more a hard-working business man than master criminal, it makes the Mafia seem a little less threatening.
But don't worry. Mara Salvatrucha, or MS-13, is a large gang that more than makes up for any crimes the Mafia missed. They are a Hispanic gang that, according to an ex-member: "[T]hey wanna be the top gang, the top Hispanic gang. That's what they want. They want to be the one with the most killings, the most murders.” (That ex-member is now dead, murdered by MS-13.) In addition to the standard organized crime goals of controlling drugs, prostitution, and theft, MS-13 also engages in human trafficking and assaults of law enforcement officials. They are, naturally, a major player in the smuggling of illegal aliens across the border.
It isn't only poor Mexicans wanting to move across the border. Al-Qaeada has also been interested. (Links here and here) So in addition to being an internal threat, this organization is also a national security threat.
The Mafia was effectively broken up during the Seventies. That won't happen with MS-13. MS-13 is based in Mexico (much as the Mafia was based in Italy) The difference is, Italy is separated from the United States by an ocean and a sea. There is nothing separating the U.S. and Mexico- and given the foot-dragging on the building of a border fence, there won't be for the foreseeable future.
We might as well get used to the idea of MS-13. Since its leadership is safe in Mexico, it will be very difficult for any US law enforcement agency to take out any leaders. Since our politicians refuse to do anything about protecting our borders, the outlook is bleak.