The Arizona Legislature gave final approval late Thursday night to a proposal that would require President Barack Obama and other presidential candidates to prove they are U.S. citizens before their names can appear on the state's ballot.
Arizona would become the first state to require such proof if Gov. Jan Brewer signs the measure into law.
Republican Rep. Carl Seel of Phoenix, the author of the bill, said the bill wasn't about opposition to Obama.
"This bill is about the integrity of our elections," Seel said.
The Arizona Republic newspaper said the Speaker of the House Kirk Adams, R-Mesa, said he backed the bill only because the final version was constitutional and required all candidates to demonstrate that they meet the individual requirements of their office.
"I believe this particular piece of legislation does not add to or detract from the qualifications for president as stated in the United States Constitution," Adams said.
Thirteen other states have considered similar proposals this year. The proposals were defeated in Arkansas, Connecticut, Maine and Montana.
The bill won final approval from the state House in a 40-16 vote.
So-called "birthers" contend since the last presidential election that Obama is ineligible to hold the nation's highest elected office because, they argue, he was actually born in Kenya, his father's homeland.
The Constitution said a person must be a "natural-born citizen" to be eligible for the presidency.
Hawaiian birth certificates
Hawaii officials have repeatedly confirmed Obama's citizenship, and his Hawaiian birth certificates have been made public.
Even though the courts have rebuffed lawsuits challenging Obama's eligibility, the issue hasn't gone away.
"It's a fringe issue in my view, and it's going to cause people to look again at Arizona and say what's all this craziness going on there," said Democratic Rep. Daniel Patterson of Tucson, an opponent of the bill.
Rep. Ruben Gallego, D-Phoenix, said he was embarrassed, the Republic reported.
"Arizona is the first state to pass a birther bill. We look pretty much backward," Gallego said. "You might as well change Arizona to Alabama."
The Arizona proposal would require political parties and presidential candidates to hand in affidavits stating a candidate's citizenship and age and to provide the candidate's birth certificate and a sworn statement saying where the candidate has lived for 14 years.
If candidates don't have a copy of their birth certificates, they could meet the requirement by providing baptismal or circumcision certificates, hospital birth records and other documents.
If it can't be determined whether candidates who provided documents in place of their birth certificates are eligible to appear on the ballot, the secretary of state would be able to set up a committee to help determine whether the requirements have been met.
The names of candidates can be kept off the ballot if the secretary of state doesn't believe the candidates met the citizenship requirement.