Drug Prohibition has failed, and will continue to fail because people want drugs and are willing to break the law to get them. The numbers tell the story. The illegal drug trade generates an estimated 200 billion dollars annually. The profits are not taxed. The US spends over 2 billion dollars to fight illegal drugs and fails miserably. But just like drug users they keep coming back for more.
The profits of the drug and other illegal trades are used by corrupt law enforcement, politicians and bankers to get and keep power. If one of them supports prohibition they are either stupid or part of the corruption.
Put the bad guys out of business and legalize. Tell the Obama administration to solve the problem once and for all.