More than half of the states have passed laws that require voters to show some form of identification before casting a ballot; nine of those have what are considered "strict" identification requirements.
About 17 of those states require that the identification include a photo, according to data compiled by the National Conference of State Legislatures, a bipartisan organization. The requirements vary from state to state.
(Related Map on NCSL's Site: States and their respective ID requirements)
Such voter-identification laws have prompted litigation across the states, as individuals and liberal groups say the rules will make it more difficult for those who are likely to vote for President Obama to cast a ballot, according to a story in The New York Times.
In The Times article, reporter Ethan Bronner described the plight of a 93-year-old Philadelphia woman who may not be able to vote because her purse, carrying her Social Security card, was stolen. An orphan with no driver's license who was married twice with several name changes in her lifetime, Vivette Applewhite will have difficulty proving her identity. She is among people suing Pennsylvania over voter ID requirements.
Said Applewhite to The Times: "They're trying to stop black people from voting so Obama will not get reelected."
The fight for each prospective vote is fierce in battleground states like Pennsylvania and Florida, but other states are also drawing attention.
During the annual NAACP conference in Houston in early July, Attorney General Eric Holder called the Texas voter-ID law a "poll tax," which drew applause from the crowd.
Gov. Rick Perry, during Obama's trip to Texas this week, called Holder's remarks "incendiary" and said that the president should apologize to the people of Texas for Holder's poll-tax remarks.
"In labeling the Texas voter-ID law as a "˜poll tax,' Eric Holder purposefully used language designed to inflame passions and incite racial tension," Perry said in a statement. "It was not only inappropriate, but simply incorrect on its face."
Supporters of the identification laws say that they're needed to protect the integrity of the votes, and many have challenged the accusations that these laws are aimed at suppressing the votes of Latinos and blacks.
A recently released study by the Brennan Center for Justice at the New York University School of Law noted that getting a free identification isn't always easy. More than 10 million eligible voters, according to the report, live more than 10 miles from an office that issues a state ID.
"People of color are more likely to be disenfranchised by these laws since they are less likely to have a photo ID than the general population," the report said.