A person shall not sell or give any alcoholic beverage to any person who has not reached the age of 21 years. A person who has not reached the age of 21 years shall not possess any alcoholic beverage for the purpose of personal consumption. An alcoholic beverage is any beverage containing one-half of one percent or more alcohol by volume.

     Except as prohibited by this section, (t)he legislature may by law establish a liquor control commission which, subject to statutory limitations, shall exercise complete control of the alcoholic beverage traffic within this state, including the retail sales thereof. The legislature may provide for an excise tax on such sales. Neither the legislature nor the commission may authorize the manufacture or sale of alcoholic beverages in any county in which a majority of the electors voting thereon shall prohibit the same.