The House of Representatives narrowly approved Gov. Bill Lee's controversial school voucher legislation Tuesday, providing the administration its most significant victory since taking office in January.

The passage was not guaranteed and only happened after a 40-minute deadlock where the vote was stuck at 49-49, in part due to an absent lawmaker.

In a dramatic turn, Rep. Jason Zachary, switched his vote after House Republican leaders held behind-the-scenes negotiations in which the Knoxville Republican received assurances about additional changes to the bill.

Zachary's change resulted in the chamber stamping its approval on Lee's school voucher-style program with a 50-48 vote.

The hours-long action in the House came after a Senate finance committee similarly approved the measure by a one-vote margin.

The moves in both chambers provide Lee's administration a significant, albeit narrow victory, just seven weeks after the governor initially announced his signature education proposal.

The education savings account bill would provide public money for parents who unenroll a student from their public school district and allow them to spend the funds on private school or other education-related expenses.

A deadlocked vote

As House members filed into the chamber Tuesday, they were met by roughly two dozen protesters, who later held signs from inside the chamber debated the legislation.

The chamber began considering the bill around 9:45 a.m. local time but did not finalize its vote until shortly before 1 p.m.

The final vote was delayed in part due to the absence of Rep. Debra Moody, R-Covington, leading the chamber to remain deadlocked for about 40 minutes.

Rep. William Lamberth, R-Portland, said the vote was held open for members to consider their decisions.

“We are just giving folks enough time to consider whether their vote is exactly what they want it to be on the board,” Lamberth said as the vote remained open, adding if Moody were present, the legislation would pass.

Zachary ultimately cast the tie-breaker, switching from an initial no vote on the measure to a later casting a vote in favor. Zachary later told reporters he switched his vote after receiving assurances from House Speaker Glen Casada, R-Franklin, that Knox County would be removed from the legislation at some point in the future.

But Democratic Caucus Chairman Mike Stewart, D-Nashville, said he has concerns about how the vote took place.

“The way the rules work, when you take a vote, you are supposed to take the vote," he said. "They don’t say you can keep it open to press for people to vote against their constituents, which happened today."

Although the decision to hold the final vote open for a prolonged period was unusual, it was not unprecedented.

Former House Speaker Jimmy Naifeh, D-Covington, once kept a vote open for nearly two hours as he unsuccessfully tried in 2002 to convince lawmakers to approve an income tax.

The chamber's approval of the education savings account plan comes four years after the House failed to approve a vouchers measure in 2016 when lawmakers tabled a bill. The Senate version of Lee's proposal differs significantly from the House version.

Since announcing the education savings account proposal in his State of the State address, the governor has routinely touted the need for the measure, arguing it will help students escape failing schools and give parents additional choices.

Opposition ahead of the vote

But critics, including many Democrats who voted against the legislation, say it could lead to fraud and gut the state's public school system, all at the cost to taxpayers. The vote was opposed by numerous Republican lawmakers as well.

Ahead of the vote, there was a flurry of amendments by Democrats calling to make changes to the proposal, including amendments would have exempted the urban districts from the program.

Rep. Jason Powell, D-Nashville, called the proposal constitutionally suspect and said it is a direct attack on Nashville’s school funding.

“It redistributes wealth and takes money away from our children,” said Powell, who unsuccessfully sponsored an amendment that would exempt the city.

Rep. Antonio Parkinson, D-Memphis, said Shelby County Schools has for years been a model of improvement for the lowest-performing schools — the district has been viewed as a national model. And he said the bill gives underperforming rural schools money while stripping funding away from urban schools.

“As we begin to tamper with something that has been working for our state, now we are going to tamper with something that brought us to the most improving in the country,” Parkinson said.

Seated above the chamber, teachers showed up to protest the bill, holding "no vouchers" signs. Teachers, civil rights groups, superintendents and school boards opposed the vote — including in the counties where students would be eligible to participate.

"The heart and soul of the bill is very simple — parents will pursue the best educational experiences for their child," said Rep. Bill Dunn, R-Knoxville, who has for years sought to pass a school voucher bill.

Lamberth, R-Portland, said ahead of the vote that the education savings account bill helps families fleeing their school districts, such as in Davidson County, find better options.

"What I hear from folks that move from Davidson County to my county (in Sumner County) is 'thank God I escaped those failing schools,'" said Lamberth, who sponsored Lee's bill.

Lee thanks House Republican leadership

After the vote, Lee thanked Republican House leadership on Twitter for the passage of his proposal. And groups for and against the bill issued statements about its passage on the House floor.

American Federation for Children Tennessee Director Shaka Mitchell said the vote marked a historic day for Tennessee’s students and parents.

"Members of the Tennessee House took a courageous stand for the right of parents to choose the educational setting that works best for their children,” Mitchell said.

But Professional Educators of Tennessee Executive Director JC Bowman said the organization opposes the legislation but said public schools don’t fear competition.

“I would challenge the Tennessee General Assembly in future legislative efforts to focus on breaking down the bureaucratic barriers that have kept educators and school districts from pursuing solutions to the unique challenges of their communities,” Bowman said.

Details of the school voucher bill

The passage of the school voucher program came after Rep. Tom Leatherwood, R-Arlington, successfully made changes to the proposal.

The House bill approved on Tuesday calls for the creation of education savings accounts that would give parents on average $7,300 in public funds for private school or other educational services and supplies. Families would need to make less than double the federal income requirement eligibility for free lunch.

The House version calls for the Tennessee Department of Education to verify the recipient's legal status in Tennessee. Students or their legal guardians would need to provide identification, including a driver’s license, passport or birth certificate, to participate.

The legal status check has drawn questions from Democrats

A 1982 U.S. Supreme Court ruling says students who entered the country illegally cannot be denied a public education. School districts currently do not ask the immigration status of students.

The bill was amended by Leatherwood to create a program that is planned to grow to 15,000 students in the state's four largest urban districts by the program's fifth year of existence. The program includes students in Hamilton County, Metro Nashville, Knox County and Shelby County school districts.

Students participating in the program would need to take the TNReady English language arts and math tests. Students would also need to take TNReady science tests in even-numbered years and social studies tests in odd-numbered years.

The plan will also send funds to urban districts based on a percentage of the students participating in the education savings account program. It's a way to help districts make up for lost revenue for the students who enroll in the voucher program.

Counties with priority schools that aren't participating in the program also will receive grants based on a percentage of how many students participate in the urban districts.

But it also cuts how much money urban districts would have received under Lee's original proposal.

Want to read more stories like this? A subscription to one of our Tennessee publications gets you unlimited access to all the latest politics news, podcasts like Grand Divisions, plus newsletters, a personalized mobile experience and the ability to tap into stories, photos and videos from throughout the USA TODAY Network's 109 local sites.

Reach Joel Ebert at jebert@tennessean.com or 615-772-1681 and on Twitter @joelebert29.

Reach Jason Gonzales at jagonzales@tennessean.com and on Twitter @ByJasonGonzales.