Members of the Congressional Black Caucus have joined a cadre of liberal activists in asking the Supreme Court to strike down a GOP-backed Indiana law requiring voters to present a driver’s license or other official photo identification before entering the polling booth.

“While photo ID [requirements] seem harmless, they are, in fact, the modern-day poll tax,” CBC member Rep. Keith Ellison (D-Minn.) said in a recent statement. “Poll taxes were used extensively throughout the South from Reconstruction through the Jim Crow era to disenfranchise hundreds of thousands of black voters.”

Ellison is one of 45 House and Senate Democrats who recently signed friend-of-the-court briefs in Crawford v. Marion County Election Board and Indiana Democratic Party v. Rokita, consolidated cases challenging the Hoosier State’s two-year-old law requiring voters to present a driver’s license, a U.S. passport, a state ID or other government-issued identification before their votes may be counted.

This is the first time that the John Roberts-led Supreme Court has heard a challenge to a state’s voter ID law, and one legal expert called it the most important voting rights case that the court has heard since the disputed 2000 presidential election.

Lawyers from both sides will argue before the court on Jan. 9. A decision in the cases could come as early as May 2008.

Under Indiana state law, registered voters without proper identification may cast provisional ballots, which are counted if proof of eligibility is presented in person to local election officials within 10 days.

Ellison and other critics of the Indiana law argue that it creates particular burdens for blacks — a demographic that leans toward Democratic candidates — the elderly and less-educated voters.

“The Indiana photo ID requirement would also have a disparate impact on African-Americans, a class of citizens specifically protected by Congressional legislation,” Ellison’s lawyers argued in court documents filed on Nov. 12. “African-American residents are less likely to own a motor vehicle and thus are less likely to have a driver’s license.”

A Washington Institute for the Study of Ethnicity and Race study cited in Ellison’s court documents suggested that 84 percent of Indiana’s registered white voters have valid identification, compared with 78 percent of registered black voters. Among unregistered voters, the study showed that 72 percent of eligible black residents possessed proper ID necessary to vote, compared with 83 percent of potential white voters.

The study also said registered voters between the ages of 18 and 34 and older than 70 were less likely to have proper identification. Registered voters with a high school degree, too, were less inclined than their college-educated counterparts to have a driver’s license, passport or other government-issued identification.

Last January, a federal appeals court in Chicago affirmed Indiana’s law. Writing for the majority, Judge Richard Posner said the more realistic potential for voter fraud trumps the unlikely prospect that modern-day voters wouldn’t possess identification necessary to go about their lives.

“It is exceedingly difficult to maneuver in today’s America without a photo ID (try flying, or even entering a tall building such as the courthouse in which we sit, without one),” Posner wrote. “And as a consequence, the vast majority of adults have such identification …”

Posner also wrote: “The Indiana law is not like a poll tax, where on one side is the right to vote and on the other side the state’s interest in defraying the cost of elections or in limiting the franchise to people who really care about voting or in excluding poor people or in discouraging people who are black.”

Senate Rules and Administration Chairwoman Dianne Feinstein (D-Calif.), House Administration Chairman Robert Brady (D-Pa.) and the House Administration Subcommittee on Elections Chairwoman Zoe Lofgren (D-Calif.) also recently wrote the court criticizing Indiana’s law, arguing that it goes beyond mandatory requirements outlined in the Help America Vote Act of 2002.

HAVA stipulated that states require first-time voters who register by mail to show a driver’s license or other government-issued identification before voting.

“Substituting its own judgment for that of Congress, Indiana has imposed an identification requirement that is inconsistent with the requirement of HAVA,” the lawmakers argued in court papers. “Federal law precludes a state from altering the requirement either by adding to it or subtracting from it.”

Justin Leavitt, a lawyer for the Brennan Center for Justice at New York University School of Law, which also has asked the court to strike down Indiana’s law, said the pending case is the most important voting-rights case since Bush v. Gore seven years ago. Leavitt also suggested that the court’s ruling on Indiana’s law — now just one of a handful in the country — may spark political battles in state legislatures nationwide, as Republican lawmakers in some states have legislation at the ready, awaiting the high court’s ruling.

“It’s a case that’s going to decide which eligible Americans are able to vote and what eligible Americans are going to be turned away from the polls,” Leavitt said. “It’s fundamentally about deciding whether a state can enact a provision that’s proven to disenfranchise a large percentage of the American electorate for no good reason.”

Leavitt added: “It’s also very clear that [the nine justices] know that this is going to affect not only elections in Indiana in 2008, but a lot of other state laws that are teed up waiting the court’s decision.”