You must show your photo ID before renting a movie, boarding a plane and getting a prescription so having a photo ID requirement is necessary to stop your vote from being cancelled out by those seeking to fraud the election system.
Senator Scott Rupp has been a consistent supporter of protecting the sanctity of your vote. He helped pass voter photo ID legislation in 2006 which was ruled unconstitutional on a court challenge. After that ruling Scott and his colleagues acted again in 2010 passed a constitutional amendment to be put the issue of a photo voter ID before the voters.
Source: http://www.ruppformissouri.com/Electionsissue.html
