WASHINGTON – The fierce battle over Pennsylvania’s voter ID law goes to trial on Monday in a state courtroom in Harrisburg. The legal fight began with a lawsuit by the American Civil Liberties Union of Pennsylvania and other groups in May 2012. A state judge temporarily blocked the voter ID law from affecting Election Day 2012, but only after the state Supreme Court intervened.

The Pennsylvania ACLU argues the voter ID law is unconstitutional because it infringes on the right to vote and could disenfranchise voters.

The legal fight in Pennsylvania stands apart from other efforts against voter ID laws because it is being fought in state court rather than federal. It also comes less than a month after the Supreme Court’s decision to strike down a central part of the 1965 Voting Rights Act thrust elections law back into the national spotlight.

Federal courts have generally approved voter ID laws if they include accommodations for those without ID cards and other provisions to ease the burden on voters. More than 30 states have some form of identification requirement.

Pennsylvania’s voter ID lawsuit is unlikely to upset the broader legal landscape, but is significant nationwide and for Pennsylvania. The state’s voter ID law and the legal fight that followed drew national attention and outrage, in part because the state is a political battleground and swing state with 20 electoral votes.

The measure’s Republican backers in the legislature and Gov. Tom Corbett defend the measure, pointing to special identification cards and other outreach efforts the state undertook prior to the election.

Whether Commonwealth Court Judge Robert Simpson’s decision to block the law last year should give the measure’s opponents hope in this new phase is unclear. Simpson only suspended the law after the state Supreme Court ordered him to re-review the law after he first declined to stop its enforcement.

Instructed to look more deeply into the state’s implementation of the law ahead of Election Day, Simpson concluded in October that the state was unprepared, saying officials had issued fewer IDs than expected.

“The gap between the photo IDs issued and the estimated need will not be closed,” he wrote. “I am not still convinced … that there will be no voter disenfranchisement arising out of the Commonwealth’s implementation of a voter identification requirement.”