The bill now heads for the House, which passed a stricter version last summer. If approved there - as is expected in that GOP-controlled chamber as early as next week - it would go to Gov. Corbett, who has said he supports the concept, and would take effect in time for the Nov. 6 election.
"This bill is a simple, commonsense measure to protect the integrity of the voting process, which is the very foundation of our democracy," said Senate Majority Leader Dominic Pileggi (R., Delaware) as debate on the bill commenced Wednesday.
One after another, Democratic senators rose to argue the exact opposite. Those senators, as well as the Pennsylvania chapter of the ACLU, said Wednesday night they would challenge the measure in court if it becomes law.
Democrats contended the bill would disproportionately hurt the elderly, the poor and the disabled, who make up the lion's share of voters who typically do not have photo IDs. Those groups also tend to vote Democratic.
Over the last year, Republican legislators in state after state have introduced similar voter ID bills - so many that the National Conference of State Legislatures, which tracks legislation nationwide, has called voter ID the hottest election-related topic.
The push for such laws, Democrats contend, is part of a national effort to skew state and federal races in favor of Republicans. "I call you a hypocrite today if you vote for this bill," State Sen. Anthony Hardy Williams (D., Phila.) said in Wednesday's debate.
Williams and other Democrats challenged Republicans to cite specific studies or evidence of voter fraud being rampant.
During the floor debate, Pileggi cited a 2005 report by an election commission headed by former President Jimmy Carter and former Secretary of State James Baker that supported the use of photo IDs - the two men called for standardized photo IDs in the states - as a way to ensure fair elections.
But neither Pileggi nor any other senator cited a specific example of fraud.
Fifteen states now require voters to present photo identification before voting, although there are court challenges against some of those laws.
In Pennsylvania, the bill would mandate that voters show a photo ID such as a driver's license; a student, county, or municipal card; or IDs from a personal-care home.
If voters show up without a photo ID, they would be allowed to cast a provisional ballot, and then would have six days to present election officials with an acceptable ID.
The state Department of Transportation would also be required to issue free identification cards to those who apply and swear they had no other acceptable proof of identity for voting.
"No voter will be turned away from the polls on election day," Pileggi said Wednesday. "That simple fact seems to get lost in some of the hyperbole surrounding this debate."
But State Sen. Shirley Kitchen (D., Phila.) noted that obtaining a "free" ID card from the state wouldn't be free - it would require applicants to first get documentation such as birth certificates, which cost money.
"We are cutting every program to make poor people more independent," said Kitchen, referring to steep cuts to health and social welfare in Corbett's proposed budget, "and we have the audacity to come up with this law. . . . It doesn't matter whether you are in Philadelphia or Berks County, poor people cannot afford to have these new laws costing them money."
Every Democrat in the Senate voted against the bill, along with three Republicans, including Sen. Stewart J. Greenleaf (R., Montgomery). He could not immediately be reached for comment Wednesday night.
Aside from Democrats and a handful of Republicans, opponents of the measure include civil liberties organizations, labor unions, the AARP, the NAACP, and the county officials who would be tasked with implementing it.
The counties, in fact, have warned legislators that mandating the extra step of checking IDs will only lead to long lines and frustration at the polls - particularly in the relatively heavy turnouts that mark presidential elections.
The legislation calls for a "soft rollout" during the April 24 primary, when voters will be asked for a photo ID but can vote even if they do not have one on hand.
The bill's supporters estimate it will cost just under $5 million to implement, including educating voters and poll workers on the change. A Harrisburg-based liberal think tank places that number closer to $11 million.
State Sen. Larry Farnese (D., Phila.) asked his Republican colleagues, "Where the heck did you find this money?"
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