The decision by Commonwealth Court Judge Robert Simpson on the law requiring each voter to show a valid photo ID could be appealed to the state Supreme Court.
However, Simpson based his decision on guidelines given to him days ago by the high court justices, and it could easily be the final word on the law just five weeks before the Nov. 6 election.
One lawyer for the plaintiffs said it appeared to be a "win."
His ruling came after listening to two days of testimony about the state's eleventh-hour efforts to make it easier to get a valid photo ID. He also heard about long lines and ill-informed clerks at driver's license centers and identification requirements that made it hard for some registered voters to get a state-issued photo ID.
The 6-month-old law — now among the nation's toughest — has sparked a divisive debate over voting rights and become a high-profile political issue in the contest between President Barack Obama, a Democrat, and Republican nominee Mitt Romney, for Pennsylvania's prized 20 electoral votes.
Pennsylvania, traditionally considered one of the most valuable a presidential swing states, is showing a persistent lead for President Barack Obama in independent polls. As a result, the state has been virtually empty of presidential TV ads and off the candidates' beaten paths to more contested states in recent weeks.
