By Cherri Gregg

PHILADELPHIA (CBS) — Pennsylvania’s new voter ID law is causing quite a stir here in Philadelphia.  About 200 people gathered today on Independence Mall for an AARP rally to support the ACLU’s lawsuit challenging the law.

Related story:  What You Need To Know About the Pa. Voter ID Law

The chant was, “Don’t block my vote!” as red AARP shirts peppered the lawn at Independence Mall, where community groups worked to energize voters in the battle over the new law.

“I’m here because it’s unlawful,” said Cynthia Louis, who identifies herself as a senior citizen.  “It’s only about trying to (oppose) votes for President Obama.”

The Senior Law Center estimate that those over age 65 are less likely than younger voters to have birth certificates, one of the critical documents necessary for a voter ID.

“One in four Philadelphians, age 80-plus, the eldest of our elderly, do not have a Penndot ID,” says SLC executive director Karen Buck.

The courtroom showdown between the Commonwealth of Pennsylvania and the ACLU over the voter ID law begins in Harrisburg on Wednesday (see related story).