Re-Legalize Pot

Once again I see that the battle lines have been drawn over the issue of marijuana legalization. Moralists who pine for the days of old tell us that if we legalize this drug, that the moral slippery slope on which our society has been sliding will escalate into a free fall into a drug-crazed world of Reefer Madness debauchery.

I have this simple question for these people: How do they reconcile their argument with the fact that marijuana was legal in the U.S. until 1937?