"I think this would be a good time for a beer," Franklin D. Roosevelt said upon signing a bill that made 3.2-percent lager legal again, some months ahead of the full repeal of Prohibition. I hope Barack Obama will come up with some comparably witty remarks as he presides over the dismantling of our contemporary forms of prohibition"”laws that prevent gay marriage, restrict cannabis as a Schedule I Controlled Substance, and ban travel to Cuba. "You may now kiss the groom," perhaps, or"”a version of the comment he once made about smoking pot"”"I inhaled"”that was the point."

Prohibition now is different from Prohibition then. When the 18th Amendment went into effect in 1920, it was a radical social experiment challenging a custom as old as civilization. Its predictable...