Punishment (discipline) works as long as their is a chance to reform. A child or anyone for that matter, will think twice before putting his hand to the flame, but only if they have the option not to. Society in the U.S. does not offer many options for the ex-criminal to live an honest life, which I suppose, is where your idea of rehabilitation fits. Let's not pretend that nature, the ultimate punisher, fails to teach. Sticks and carrots are both effective ways of driving a horse.