
There have been only a small number of fraud cases resulting in a conviction.
Per federal law, first-time voters who registered by mail must present a photo ID or copy of a current bill or bank statement.
Indiana in 2006 became the first state to enact a strict photo ID law, a law that was upheld two years later by the U.S. Supreme Court.
How many voters might be turned away or dissuaded by the laws, and could they really affect the election?
In late September, an analysis by Reuters and research firm Ipsos of data culled from 20,000 voter interviews found that those lacking proper ID were less likely to vote anyway, “regardless of state law changes.”
Among those who said they were “certain to vote,” only 1 percent said they did not have proper ID while another 1 percent said they were uncertain whether they had the proper ID.
In Indiana and Georgia, states with the earliest versions of photo ID laws, about 1,300 provisional votes were discarded in the 2008 general election, later analysis has revealed.
As for the potential effect on the election, one analysis by the New York Times estimates they could decrease voter turnout anywhere between 0.8 and 2.4 percent.
http://www.propublica.org/article/everything-youve-ever-wanted-to-know-about-voter-id-laws