The bill, which would give Pennsylvania one of the nation's toughest voter ID laws, was expected to pass Tuesday in the Republican-controlled House, the last step before it can go to the desk of Gov. Tom Corbett, who plans to sign it.
Democrats have fought the bill, bitterly denouncing it part of a wider GOP plot nationwide to suppress votes during a presidential election year by traditional Democratic constituents, such as the poor, disabled or elderly, who may not have ID or may have difficulty getting ID.
"I think it is a surreptitious attempt to suppress the Democratic vote, using tax dollars," said Rep. Greg Vitali, D-Delaware, told colleagues during debate Monday. "It is wrong, it is insidious."
It passed the state Senate last week.
On Monday, Democrats attempted to amend the bill in various ways, including trying to delay it from taking effect until 2013 or allowing Medicare enrollees to present their Medicare ID cards as valid identification. Republicans rejected the attempts, both in committee and on the House floor.
Republicans point to the wide use of photo IDs for things like prescription drugs or boarding airplanes, and say that legitimate voters deserve to have their votes protected from being diluted by fraud, but Republicans are also hard-pressed to find examples of voter fraud.
They point instead to examples of voter registration violations, such as the 2008 and 2009 arrests of some voter-registration workers connected with the ACORN activist group in Pennsylvania as evidence of the need for the bill.
They also say illegal immigrants have received voter registration cards and that the state's election system lacks adequate safeguards to stop voter registration fraud - an assertion that the county commissioners association disputes.
"This is to ensure one person votes one time," Corbett, a Republican, told a Pennsylvania Cable Network interviewer on Monday.
Corbett added that some precincts in the past have voted over 100 percent, which he said demonstrates fraud, but he did not give examples in the interview. His top elections official, Secretary of State Carol Aichele, could not cite any instances of voter fraud when asked by a member of the Senate Appropriations Committee earlier this month.
The County Commissioners Association has warned that adding the photo ID step will create longer Election Day lines at polling places. The association also has said county commissioners have not heard allegations of voter impersonation, and that current law provides adequate safeguards against fraud in the voter registration process and at the polls on Election Day.
People applying to register to vote are required to submit identifying information, such as a driver's license number, that county officials cross-check against government databases. If they pass muster, the voter identification card is mailed to the applicant's home address in an envelope cannot be forwarded.
Republicans insist that no one will be turned away from a polling place. Anyone who doesn't have the required ID could cast a provisional ballot before being allowed six days to get an acceptable ID and go to county offices to show it to election officials, or mailing, emailing or faxing a copy, they said.
To address any suggestion that a photo ID requirement amounts to an unconstitutional "poll tax," the state Department of Transportation would be required to issue an identification card at no cost to anyone who applies and swears that he or she has no other proof of identification allowed under the law for voting purposes. PennDOT has 71 license-making offices.
But Democrats argued that getting an ID involves hurdles. For instance, arranging the extra trips will be difficult for some people, they said, while getting a Pennsylvania state ID card requires showing a Social Security card, a birth certificate or certificate of residency, and two proofs of residency, such as a lease agreement, utility bill or a tax record.
Rep. Jennifer Mann, D-Lehigh, said Monday that her constituents seeking birth certificates have been told by state offices that they must wait four to five months.