State House and Senate negotiators Thursday reached agreement on a proposed constitutional amendment that would ask voters next year whether public money should be spent on private preschool.

The proposed constitutional amendment, which now goes before the full House and Senate, is critical to Gov. Neil Abercrombie’s early-childhood education initiative. Without the amendment the state would not be able to use public money to build the necessary capacity at public and private preschools to eventually serve all of the state’s 18,000 4-year-olds.

An interim school readiness program, still under review by lawmakers, would serve 3,500 4-year-olds next year who otherwise would have been eligible for junior kindergarten, which is being eliminated.

"I think it really is about making sure that this message and this vote can go to the people and they can show that it really is time that Hawaii join the vast majority of states in publicly funding early learning for our youngest of keiki," said Sen. Jill Tokuda (D, Kailua-Kaneohe), the lead Senate negotiator on early education. "This is a huge step for Hawaii, and I think it’s one that we should be very proud of."

Tokuda said negotiators will likely wait to see whether money for Abercrombie’s early-education initiative is included in the state’s two-year budget, which is expected to be finalized early next week, before advancing the companion school readiness and early-learning bills. The Abercrombie administration has asked for about $25 million for early education over the next two years, but the price tag could grow to more than $125 million annually if early education is expanded to cover all 4-year-olds.

Terry Lock, director of the Executive Office on Early Learning, said many other states with state-funded preschool have made use of both public and private preschools.

"We want to build on the private-sector (schools) that are already there," she said. "It’s an economic move on our part."

Article X, Section 1, of the state Constitution prohibits public funds from being spent to support or benefit any sectarian or nonsectarian private educational institution.

The proposal for the constitutional amendment would ask voters in November 2014 whether public money could be used to support private early-education programs that do not discriminate on the basis of race, religion, sex or ancestry.

Two-thirds votes in both the House and Senate are required to put the amendment before voters, or majority votes this session and next session.

Tokuda and Rep. Roy Takumi (D, Pearl City-Wai­pio-Pearl Harbor), the lead House negotiator, are optimistic they will have the two-thirds votes necessary this session.

But lawmakers are receiving pressure from the Hawaii State Teachers Association and from advocates for religious preschools to defeat the proposal for the constitutional amendment.

The HSTA contends that the early-education initiative is too much like a voucher program that could divert public money away from public schools.

"If it walks like a duck and quacks like a duck, it’s not a chicken," said Al Naga­sako, the HSTA’s executive director.

Walter Yoshimitsu, executive director of the Hawaii Catholic Conference, said he would prefer a voucher program so that religious preschools could participate in the early-education initiative without downplaying religion. Otherwise, religious preschools could be barred from proselytizing, displaying religious symbols and discriminating in hiring in order to participate in the state-funded program.

Yoshimitsu said religious preschools want to be involved "without compromising the religious aspect of the school."