Tomorrow the Commonwealth Court of Pennsylvania will hear a challenge to the state’s new voter ID law from the ACLU and other voting rights groups. The lead plaintiff is Viviette Applewhite, a 93-year-old great-great grandmother who marched with Martin Luther King Jr. Applewhite worked as a hotel housekeeper and never had a driver’s license. Four years ago, her purse was stolen and she lost her Social Security card. Because she was adopted and married twice, she cannot obtain the documents needed to comply with the state’s voter ID law. After voting in every election for the past fifty years, she will lose the right to vote this November.

The ACLU will argue that Pennsylvania’s voter ID law needlessly disenfranchises voters like Applewhite and violates Article I, Section 5, of the state constitution, which states: “Elections shall be free and equal; and no power, civil or military, shall at any time interfere to prevent the free exercise of the right of suffrage.” As in Wisconsin, where two federal judges have blocked that state’s voter ID law, the Pennsylvania Constitution affords strong protections to the right to vote. (The Justice Department is also investigating whether the law violates Section 2 of the Voting Rights Act.)

Recent developments in Pennsylvania have transformed the debate over voter ID laws locally and nationally. The first turning point came last month, when Pennsylvania GOP House Leader Mike Turzai said the voter ID law “is gonna allow Governor Romney to win the state of Pennsylvania.” Turzai’s comment clarified, once and for all, the real intent of GOP-backed voter ID laws. They’re not aimed at combating the phantom menace of voter fraud—indeed, Pennsylvania just admitted in court filings that there “have been no investigations or prosecutions of in-person voter fraud in Pennsylvania”—but rather at suppressing Democratic turnout in order to benefit Republican candidates.

The second turning point came a few weeks later, when the Pennsylvania Transportation Department found that 9.2 percent of registered voters, 758,000 Pennsylvanians, don’t have the state-issued IDs required to vote under the law. The number of voters without ID was larger than the margin of Barack Obama’s victory over John McCain in Pennsylvania in 2008. That bombshell contradicted Pennsylvania Secretary of State Carol Aichele’s oft-repeated claim that 99 percent of eligible voters possessed the requisite IDs. The Department of Transportation didn’t release the exact demographic breakdowns of who did not have IDs, but it did find that 18 percent of voters in Philadelphia, a heavily Democratic city that is 44 percent African-American, did not have valid state-issued IDs.

In fact, the number of voters lacking voter ID may be even higher than the state’s estimate. According to a new study [pdf] by University of Washington political scientist Matt Barreto, more than 1 million registered voters in Pennsylvania—12.8 percent of the electorate—don’t have valid voter ID. Furthermore, only 34 percent of registered voters are aware of the law but 98 percent of registered voters believe they have the right ID. That’s a huge gap between perception and reality with regards to the law.

Who are the voters without ID? Writes Barreto:

“There are several statistically significant differences in possession rates of valid photo ID across subgroups of the population. Specifically, female eligible voters lack ID at higher rates (17.2%) than do males (11.5%). Latino eligible voters lack ID at higher rates (18.3%) than do non-Hispanic Whites (14.0%). The elderly (over age 75) lack ID at higher rates (17.8%) than middle-aged residents (10.3%) and younger respondents (age 18-34) also lack at higher rates (17.9%). Eligible voters who make less than $20,000 annually are more likely to lack a valid photo ID (22%) than all other income categories, most notably those who make $80,000 or more (8.2%), and finally 18.5% of respondents who did not complete high school lack an ID compared to 8.3% among college graduates.”

Moreover, obtaining the correct ID from the state isn’t as easy as one would presume, Barreto notes. 

“In order to obtain a valid photo ID, residents of Pennsylvania need to provide documentary proof of citizenship, a Social Security card, and proof of address. Among eligible voters who currently lack a valid ID, 27.6 percent do not have at least one of the three required underlying documents needed to obtain a valid photo ID. Overall, this represents an estimated 379,009 citizen, adult, eligible voters in Pennsylvania.”

According to the Brennan Center for Justice, 2 million Pennsylvanians—24 percent of state’s voting-age citizens—live more than ten miles from the nearest DMV or ID-issuing office. Of that number, 135,000 people don’t have a car.

In response to public outcry, Pennsylvania has decided to make available a backup ID for those who cannot produce the documentation necessary to obtain the original voter ID card. The program is supposed to begin next month, but it’s unclear how many Pennsylvanians without ID will take advantage of it or be able to comply with the requirements—two proofs of residence, date of birth and Social Security number. It doesn’t help that the voter education component of the law is being run by GOP operatives with close ties to GOP Governor Tom Corbett and the Romney campaign.

For all these reasons, the trial in Harrisburg tomorrow will have major implications for the 2012 election in Pennsylvania and nationally. Turzai, sadly, will not be testifying on behalf of the state.