Pennsylvania's tough new voter identification law is on trial in Harrisburg. Several voting rights groups argue that the law is unconstitutional.
The law, if implemented, would require voters to show photo ID to cast a ballot. The photo ID also needs to have an expiration date.
Governor Tom Corbett signed the law in March of 2012, but courts have blocked its enforcement.
Critics say the law is a Republican attempt to discourage voting by Democratic leaning voters.
According to the ACLU, as many as five percent of Pennsylvania's eligible electorate may be barred from voting under the new law.
Supporters say the law discourages voter fraud by preventing someone from impersonating and casting a fraudulent ballot