In his 70-page opinion, handed down Wednesday morning, Judge Robert E. Simpson Jr. said the challengers had not shown that "disenfranchisement was immediate or inevitable." He found that requiring photo ID at the polls is a "reasonable nondiscriminatory, non-severe burden when viewed in the broader context of the widespread use of photo ID in daily life."
Simpson also ruled that the state has a "relevant and legitimate interest" in ensuring the integrity of elections, and that that goal was important enough to "justify the burden" the new law imposes on voters.
"The statute simply gives poll workers another tool to verify that the person voting is who they claim to be," he wrote.
The American Civil Liberties Union and other groups representing eight plaintiffs, several of whom testified that they lacked photo ID for various reasons and would be unable to vote in November, argued that the law was unconstitutional because thousands of people - if not hundreds of thousands - could be similarly disenfranchised.
The groups said they would file an appeal with the Pennsylvania Supreme Court on Thursday and seek an expedited ruling.
It was not clear how quickly the high court might act. The court is not scheduled to meet again until Sept. 10, when it convenes in Philadelphia, but that does not rule out the possibility of an earlier ruling, said Art Heinz, a court spokesman.
Though judges are barred from letting party loyalties influence their decisions, those loyalties have been a subject of constant speculation in the case. Simpson is a Republican; the state Supreme Court, with one Republican member suspended because of her own legal troubles, is now split 3-3 between Democratic and Republican justices. A tie would uphold Simpson's ruling.
His ruling placed considerable emphasis on case law established by both the U.S. Supreme Court and other state courts ruling on similar election regulation issues.
He said the plaintiffs did not prove that leaving the law in place would cause "greater injury," and noted that halting the process would interfere with election machinery now in motion to prepare for the Nov. 6 vote.
Reaction was swift from all quarters in the closely watched case. Gov. Corbett and Republican elected officials praised the judge for upholding a law they say will protect honest voters by curbing election fraud, while Democrats expressed deep disappointment, saying the law would disenfranchise hundreds of thousands of voters while also vowing to step up their campaign to ensure all voters have proper ID.
On that score, at least, they found common ground with Corbett. Now that the law has been upheld, the governor said in a statement, "we can continue to focus our attention on ensuring that every Pennsylvania citizen who wants to vote has the identification necessary to make sure their vote counts."
Penda Hair, an elections law attorney for the Advancement Project, a civil-rights group that also argued on behalf of the plaintiffs, called the ruling "a huge setback for the right to vote."
"It's contrary to core American values and sadly takes us back to a dark place in our country's history," Hair said. "We hope the Pennsylvania Supreme Court will see through this and affirm that all Pennsylvania voters have a right to be heard at the ballot box."
In his ruling, Simpson said the plaintiffs' lawyers "did an excellent job of 'putting a face' " on voters who face added burdens because of the new law's photo-ID requirements."
"At the end of the day, however, I do not have the luxury of deciding this issue based on my sympathy for the witnesses or my esteem for counsel. Rather, I must analyze the law, and apply it," he wrote.
Simpson ruled that contrary to the plaintiffs' contentions - and the chorus of criticism from Democrats - the law is neutral, nondiscriminatory, and applies uniformly to all Pennsylvania voters. Speculation about the potential problems in issuing valid photo IDs or any confusion that the law might create on Election Day did not warrant "invalidation of all lawful applications" of it, his opinion said.
Attorneys for the plaintiffs contended that Simpson should have applied the "strict scrutiny" standard, which would have placed a greater burden on the state to justify the new law, but instead he gave deference to the well-established power of the legislature to regulate elections.
Still, the judge was not entirely kind to legislators. He chastised House Majority Leader Mike Turzai for what Simpson termed the Republican's "disturbing, tendentious statements" in June asserting that the law would help GOP presidential candidate Mitt Romney win Pennsylvania. The plaintiffs had cited Turzai's words as evidence of underlying partisan motives for the law.
Election-law expert Rick Hasen, a professor at the University of California, Irvine, said that while he did not support Simpson's ruling, it was consistent with other courts' rulings in similar voter ID cases - such as the U.S. Supreme Court's 2010 decision upholding Indiana's law.
"Whether you like it or not," Hasen said, "... it's not as if he went out on a limb on that."
But Janai Nelson, an elections law expert at St. John's University School of Law in New York City, said the judge failed to recognize what Nelson called the immediate harm of enforcing the new ID requirement with the presidential election now just 83 days away.
"Instead, the court places great faith in a political process that is fraught with partisanship to protect voter's rights," she said.
Lawyers for the Corbett administration had acknowledged before hearings in the case that they were offering no evidence that Pennsylvania had seen the kind of in-person election fraud that the law's sponsors said it was crafted to prevent. They contended they didn't need to.
Simpson agreed, saying the lack of such evidence was irrelevant. He wrote "absence of in-person voter fraud in Pennsylvania is not by itself dispositive."
Judicial Watch, the national conservative legal advocacy group that filed a friend-of-the court brief in the case, said the voter-ID law will boost public confidence in the integrity of elections.
"Be assured that we are prepared to defend this law before the Pennsylvania Supreme Court if need be," said the group's president, Tom Fitton.
Reaction to the Simpson ruling among election officials was split along party lines - much like the voting in the Republican-controlled General Assembly that enacted the voter-ID legislation in March.
Corbett and Secretary of the Commonwealth Carol Aichele, whose office oversees elections, promised to focus their attention on providing citizens with the ID they'll need to vote in November.
"We will continue our outreach efforts to make sure all legal Pennsylvania voters know about the law, and know how to get a free ID to vote if needed," the governor's statement said.
Turzai (R., Allegheny) called it a "commonsense decision" that understood the importance of "protecting the integrity of each and every vote." His statement did not mention the judge's criticisms of the comments Turzai had made in June to a Republican State Committee meeting that the new law would "allow Gov. Romney to win the state of Pennsylvania."
Simpson concluded that there was no evidence other lawmakers shared Turzai's "boastful views."
Contact Amy Worden at 717-783-2584 or firstname.lastname@example.org, or follow @inkyamy on Twitter.