Republican lawmakers Alan Clemmons and Chip Campsen said their legislation would combat election fraud and is not racially motivated, McClatchy Newspapers reported Tuesday.
The two were questioned in federal court by lawyers from the U.S. Justice Department and civil rights groups who charge the purpose of the law is to suppress the votes of African-Americans who overwhelmingly support Democratic candidates.
Staff attorney Nancy Abudu of the American Civil Liberties Union said requiring voters to show a photo ID "disproportionately impacts minorities, the elderly and other groups."
"We're here to protect people's constitutional right to vote," she said in an ACLU release.
Implementation of the measure, signed into law by Gov. Nikki Haley in May 2011, was blocked by the Justice Department for violating the 1965 Voting Rights Act that requires South Carolina to submit all election changes to federal review.
South Carolina filed suit against the Justice Department for blocking the ID law.
The case is expected to eventually make its way to the U.S. Supreme Court.