"If they do not, or if Commonwealth Court is not still convinced in its predictive judgment that there will be no voter disenfranchisement arising out of the commonwealth's implementation of a voter identification requirement . . . that court is obligated to enter a preliminary injunction," the majority said in an unsigned opinion.
The justices gave Simpson until Oct. 2 - just five weeks before the presidential election - to decide.
The majority included Chief Justice Ronald D. Castille and J. Michael Eakin and Thomas G. Saylor, all elected as Republicans, and Max Baer, who ran as a Democrat.
The dissenters, Debra McCloskey Todd and Seamus McCaffery, both elected as Democrats, chastised their colleagues for not acting directly to block the photo-ID requirements from affecting the Nov. 6 vote.
"I have heard enough about the commonwealth's scramble to meet this law's requirements," Todd wrote. "There is ample evidence of disarray in the record. . . . Seven weeks before an election, the voters are entitled to know the rules. ... The eyes of the nation are upon us, and this court has chosen to punt rather than to act. I will have no part of it."
Though McCaffery said he had no quibble with requiring voters "at some reasonable point in the future" to present photo ID at the polls, he pointed to state House Republican leader Mike Turzai's June statement that the new law would allow GOP presidential candidate Mitt Romney to carry Pennsylvania. McCaffery wrote that "it is clear to me that the reason for the urgency of implementing Act 18 prior to the November 2012 election is purely political."
The majority opinion described voting as a fundamental right and appeared to shift to state officials the burden of convincing Simpson that implementing the voter-ID law would result in "no voter disenfranchisement."
"That's a very tough standard to meet," said David Gersch, one of the attorneys fighting the law on behalf of individual plaintiffs as well as civil-rights and civic groups, including the League of Women Voters and the NAACP.
The opinion said the state's effort to implement the law was "by no means seamless."
When the case was argued before the high court last week, Saylor noted that the state had not followed the letter of the law, which requires PennDot to provide a nondriver photo ID card for free to any registered voter who swears he or she needs it for voting purposes - "a policy of liberal access," as the majority put it Tuesday.
But state officials said federal Homeland Security requirements prevented PennDot from being so lenient - so the Corbett administration's Department of State, which oversees elections, imposed tougher rules on issuance of the nondriver IDs.
That department "has realized, and the commonwealth parties have candidly conceded, that the law is not being implemented according to its terms," the opinion said.
Initially, the state required voters needing photo IDs to provide certified birth certificates, Social Security cards, and proofs of residence. On the eve of Simpson's hearings, it announced a new plan to issue photo ID good for voting purposes only, requiring voters simply to give their dates of birth and Social Security numbers, along with documentation of residency.
Even with those eased requirements, the numbers of people seeking photo ID from PennDot have been significantly lower than the number of voters thought to need it.
Since March, when Republican lawmakers passed the voter-ID law and Gov. Corbett signed it, through the end of last week, the state had issued only 8,165 nondriver IDs for voting purposes - and over the last three weeks, just 807 of the voter-only IDs, said Jan McKnight, a PennDot spokeswoman.
By comparison, estimates of those needing to obtain voter-ID cards to comply with the new law have ranged from around 80,000 to more than 10 times that number.
Critics of the law have contended that hundreds of thousands of registered voters still do not have one of the forms of photo ID required by the law. Those include a driver's license, U.S. passport, government employee ID card, U.S. military ID, student ID from Pennsylvania colleges, or ID from licensed Pennsylvania care facilities. In most cases, the IDs must be current, with specified expiration dates.
"Overall, we are confronted with an ambitious effort on the part of the General Assembly to bring the new identification procedure into effect within a relatively short time frame and an implementation process which has by no means been seamless in light of the serious operational constraints faced by the executive branch," the Supreme Court majority said.
"Given this state of affairs, we are not satisfied with a mere predictive judgment based primarily on the assurances of government officials, even though we have no doubt they are proceeding in good faith."
Corbett took comfort from that. "I am pleased that the state Supreme Court recognized that we have been working hard, and in good faith, to implement the voter ID law," he said in a statement. "My administration will continue to work hard to ensure that Pennsylvania voters know about this new law and help them obtain the proper identification to vote on Election Day."
State Rep. Daryl Metcalfe (R., Butler), the voter-ID law's original sponsor, said he was disappointed.
The legislature's right to regulate elections "is very clear throughout the history of Pennsylvania," Metcalfe said. "The courts should have declared that and stepped aside; instead they played this game they are playing, kicking it down to Commonwealth Court."
State officials' creating of the voting-only card "has no basis in law," Metcalfe said. "They really muddied the waters when they came up with this new scheme."
State Sen. Daylin Leach (D., Montgomery) said he had hoped the court would strike down the law, but found much to like in the decision, such as the directive that Simpson block the law if he finds the state has not done enough to provide IDs to voters. "I'm optimistic about the trajectory this is taking," he said.
The state GOP chairman, Rob Gleason, predicted the law would ultimately be upheld, and pointed to a poll showing wide support for it.
"Even The Philadelphia Inquirer reported, just last Sunday, that two-thirds of likely Pennsylvania voters support the state's new law requiring official photo ID to vote. What's more, 94 percent of those polled said it would not be difficult for them to obtain the necessary ID," his statement said. "Clearly, this legislation is in line - and in touch - with the view of Pennsylvanians, despite the hysteria created by some in the media."
Contact Bob Warner at 215-854-5885 or firstname.lastname@example.org.
Inquirer staff writers Jessica Parks and Amy Worden contributed to this article.