Not commonly known is the fact that there was a monetary motivation for the 18th amendment.  John D. Rockefeller gave over $30,000 to the Woman's Christian Temperance Union (http://www.rockarch.org/collections/family/jdrsr/cc/sumwyz.php) which in today's dollars would probably be over $15,000,000 to help fight for prohibition, not temperance.  He may have believed in the cause, but he also stood quite a bit to gain because with alcohol out of the way, the fuel for the new boom of motor cars would become gasoline, which was produced by Rockefeller's Standard Oil monopoly.