Haven't they already identified themselves though? You can't just show up anywhere in the country and cast a vote right?
What about absentee ballots? They don't show up at the designated polling station and show I.D. We would have to do away mail in ballots completely since there is no official to check your photo id against the rolls.
The type of voting fraud that a state issued I.D. would stop is infintesimal. It's just too inefficient to work and the penalty is a big fine and 5 years in prison.
This is from a 2012 article and it'll give you some perspective:
Over the past decade Texas has convicted 51 people of voter fraud, according the state's Attorney General Greg Abbott. Only four of those cases were for voter impersonation, the only type of voter fraud that voter ID laws prevent.
Nationwide that rate of voter impersonation is even lower.
Out of the 197 million votes cast for federal candidates between 2002 and 2005, only 40 voters were indicted for voter fraud, according to a Department of Justice study outlined during a 2006 Congressional hearing. Only 26 of those cases, or about .00000013 percent of the votes cast, resulted in convictions or guilty pleas.