As written, the law says voters who do not bring proper photo ID on Election Day can cast a provisional ballot. They would then have six days to bring in the required photo ID for their votes to count.
Simpson told attorneys in the case that he was trying to figure out how to address what he called the "offending" parts of the law without throwing the measure out. He said the law does not disenfranchise voters simply because it requires poll workers to ask for photo ID. Rather, the risk comes when a voter casts a provisional ballot but then cannot obtain the necessary identification in time.
"What I'm thinking is blocking implementation of one specific section that contains disenfranchisement language," Simpson said from the bench.
"The provisional ballot seems to be the sticking point," he said. "It's not the smoothest part of" the voter-ID law.
He did not offer further detail about what else an injunction might include - such as what other requirements, if any, voters casting provisional ballots would have to meet.
Attorneys for the plaintiffs, which include civil rights and other civic groups, are seeking to block the entire law until a trial can be held on its merits. In court, they argued that anything but a broad injunction would cause confusion and send a conflicting message to voters about what they need in order to vote.
Witold "Vic" Walczak, state legal director of the ACLU and one of the plaintiffs' attorneys, noted that an injunction narrowly targeting provisional ballots would tread on the fine line of rewriting the law the legislature had penned.
The end result, Walczak said in court, is that people will still think they need photo IDs to vote, and if they cannot obtain them by Election Day, "folks will stay home."
Simpson has until Tuesday to decide whether to block the law from taking effect. He said earlier this week that he did not want to wait until the last minute. He gave both sides until day's end Friday to submit post-hearing motions.
Simpson previously rejected contentions that the law put too many burdens on voters. On appeal, the state Supreme Court sent the case back, saying the central question for him to decide was whether the state had done a good enough job at getting IDs to any voter needing one.
On Thursday morning, more than a half-dozen witnesses took the stand to describe their difficulties in getting photo ID from the Department of Transportation.
Doris Clark described an ordeal. The 68-year-old Philadelphian testified that it took her nearly three months and three visits to PennDot to get photo identification - and that she only got a picture ID card in the end because she got angry and yelled at the clerks.
"I said, 'I'm just not going to vote then, I'm tired,' " testified Clark, who said she has been voting regularly since she was 21, and who had a hard time getting ID first because her married name did not match her maiden name on her birth certificate, and later because PennDot clerks would not accept a letter from federal officials with her Social Security information.
Jessica Hockenbury of Pittsburgh testified of having spent almost two days trying to get the state's voting-only ID, with its less-stringent identity requirements. Hockenbury, 19, said PennDot staffers gave her wrong and often conflicting information.
Critics of the law have argued that it is being rushed into effect - it was enacted by the Republican-controlled legislature in March - and will disenfranchise hundreds of thousands of voters.
State officials have described steps they have taken to educate voters about the law and provide free IDs. At the start of this week's hearing, officials said they would relax requirements for the voting-only picture ID.
Under the new plan, voters should be able to apply for a voting-only ID at a PennDot center without first seeking a nondriver ID, and without having to show proof of residence. They will still have to give their Social Security number. If the application cannot be processed immediately, PennDot will still take a photo and, if there is no problem, mail the card.
The ACLU's Walczak urged Simpson not to put too much stock in the new plan. He noted that state officials, while well-meaning, had made promises before about helping voters get IDs, but that problems persisted. He said the plan amounted to conceding that past steps failed.
"There are glitches," he said. "There is no way these officials can give assurances that no one will be disenfranchised."
Lawyer Alicia Hickok, representing the Corbett administration, countered that the plaintiffs' witnesses were merely "resentful" about the process of getting IDs. "But frustration," she said, "is a part of everyday life."
Asked later if she believed most of the law would be left intact, Hickok said: "I believe he would not strike down the entire law. But I cannot speak for what a court will determine" as he reviews the evidence in argument.
Contact Angela Couloumbis at 717-787-5934 or firstname.lastname@example.org, or follow on Twitter @AngelasInk.