Violence is only a temporary solution to drug problem. I think it's really hard to eliminate drugs because it's a big and dirty business handled by organized and untouchable syndicates. Violence will only result to numbers of death and it will only cause people lose trust in the government. Violence is not the best way to control everything.
When people are desperate for a solution, they don't really care how bad or practical that can be. They just want the results, although it will be a temporary one. Look at what is happening in the Philippines. The war on drugs has succeeded in reducing the crime rate and decreasing the number of drug addicts. But we need to see, whether this is a temporary effect, or a permanent one.