The cost of the "recovery" programs are a minor issue compared to the "welfare" programs.
"The cost of the "recovery" programs are a minor issue compared to the "welfare" programs."
That's probably true. So to remain true to libertarian principles, you cannot legalize drugs unless you also eliminate welfare. I think Friedman would agree with that.
Unfortunately, I think many people get it exactly backwards. I generally like Bill O'Reilly, for example, but he thinks we should crack down hard on drug usage but provide government-run rehabilitation programs.
On a related topic, I once heard Friedman say that he would generally be for open borders except for the fact that we have a welfare system that attracts unproductive immigrants. Get rid of welfare (and similar hand-out programs), and the borders take care of themselves, more or less.