There are a couple of paths that need to be addressed. The first is the second part of the question. History shows that dictators have been able to use force to eliminate the issue of organized crime. For example, Benito Mussolini declared war on the mafia in 1920s Italy. He empowered members of his government, such as Cesare Mori, to do whatever it took to root out firmly embedded elements of organized crime in Italy. As a dictator who wanted to get rid of organized crime, Mussolini provided a template in that he simply used his powers and unlimited national resources to fight a local problem. It is here where the dictator can manipulate the situation to their advantage. Organized crime is effective because it is local. Even with syndicates, the effectiveness of organized crime is in its intimacy and locality. The dictator has national resources that it can target at a local industry. Dictators have the luxury of not needing to "understand" the problem. If the goal is to eliminate organized crime, the dictator can simply use the resources of a national office and be able to "outgun" the local organized crime outfit. Mussolini embraced torture, intimidation, and techniques that would put the organized crime chieftains to shame and the result was imprisonment or exile for many criminal families. This would be one approach that a dictator can take.
Continuing with the dictator approach to "solving" the problem, an autocratic rule could simply appropriate the organized crime syndicate as part of an "enforcement" wing of their rule. The organized criminal activity is rooted in brute enforcement and intimidation. A dictator is very close to a political representation of this. A dictator could conceivably "solve" the problem by taking over one of the organized criminal factions and using their power in political office and resources to wipe out the opposing factions. This would reduce organized crime and gangs, and solidify the power of the dictator. The tables would be turned in that the dictator would be able to approach the leaders of organized crime in an ultimatum manner: Either there is compliance or there is going to be trouble. In this way, a dictator could eliminate the problem of organized crime by making the organization part of their own organization apparatus. Granted, this is not political idealism and it does not speak to the values of a society that embraces civil discourse, justice, and fairness within the law. Yet, a dictatorship is not really concerned with these ends. Power is the driving force behind a dictatorship on a national scale, and it is the motivating factor for the organized criminal faction on a smaller one. The political appropriation of an organized crime faction can help to reduce the overall problem of gangland activity and organized crime behavior.
If we move away from the fiat power of the dictator, there are some steps that can be taken by civic minded governments and representative leadership in addressing the issue of organized crime and gangs. These elements must seek to understand the problem and in grasping its implications, gangs and organized crime can be eliminated. The first step is to gather ground intelligence. Gang activity cannot be addressed in a strictly unilateral manner. It does not go away with "top down" initiatives. Rather, there has to be a "boots on the ground" approach where law enforcement brings in local agencies and local civilians, as opposed to alienating them. Gangs and organized crime thrive on a street by street, block by block approach. When law enforcement initiatives are focused on countering this incrementally, through contact and resource information sharing, there is a better chance of "taking back neighborhoods" away from gangs and organized crime elements. Leaders who wish to eliminate gangs and organized crime have to establish firm outreach in the areas most impacted by criminal activity. They must be able to know who is being impacted and counter it by giving afflicted individuals and areas an alternative path.
Another approach that has proven to be successful is to target at- risk youth. Gangs and organized crime suffer greatly when young people have the strength and capacity to turn from it. In the same way, when young people fill in the ranks of criminal organizations, nefarious activity thrives. Comprehensive anti- gang enforcement is rooted in ensuring that youth that are at- risk have another avenue that can be realistically embraced as opposed to criminal activity:
Evaluation research has identified programs that have demonstrated effectiveness in reducing the impact of risk factors. These efforts have identified that responses must be comprehensive, long-term strategic approaches that contain the spread of gang activity, protect those youth who are most susceptible, and mitigate risk factors that foster gang activity.
Of the varied approaches that need to be taken in curbing gang and organized criminal activity, ensuring that at- risk youth receives attention and focus is essential. In addition to this, large scale initiatives that target organized criminal activity and gang violence is critical. In these approaches, representative government can speak effectively to the issue of organized crime and gangs.
Throughout history a lot of conflicts, including organized crime, has just been taken care of using force, violence, or military action. While this is effective I don't think it is the best way to eliminate organized crime forever. If I were a dictator, I would want to find the main source of the crime, whether it be a leader or a select group who ran everything in the city. I would put them in jail immediately and then if crime continued I would probably resort to military force (without hurting innocent people). I would also want to increase police force around the areas crime was happening in the most. Although we don't here about as many gangs today as we used to, they do exist and most are stopped using police force which works well.
In my opinion one of leading causes of gangs is a lack of strong youth programs.
If everyone felt like they belonged somewhere and no one felt left out, there would be no need to join a gang. If I were a dictator I would make sure that every adolecent and young adult was involved in some sort of after school/ recreational activity.