It defined as being illegal items with more than one-half of one percent of the involved substance.  
It was supported by rectangular yellow pamphlets encouraging voters to vote yes on May 24 "for the sake of our boys and girls."  This support was galvanized by the WCTU and was lobbied for in Washington under the aegis of its formulator Wayne Wheeler.  It was sponsored by the chair of the House (*) Judiciary Committee, a congressman from Minnesota, and it gave power of enforcement to the Commissioner of Internal Revenue.  It defined as being illegal items with more than one-half of one percent of the involved substance.  FTP, name this act passed in 1919 to enforce the 18th Amendment and which began the era of Prohibition.
It was supported by rectangular yellow pamphlets encouraging voters to vote yes on May 24 "for the sake of our boys and girls."  
Volstead Act (accept early 18th Amendment before *)