PHOENIX – Arizona lawmakers could soon greatly expand the state’s K-12 education voucher program with a recently amended bill pending in the legislature.

Arizona’s House Bill 2291, sponsored by Republican Rep. Debbie Lasko, was recently amended to expand the state’s existing Empowerment Scholarship Account (ESA) program to all students in schools with large low-income populations, the Associated Press reports.

The Empowerment Scholarships – also known as education savings accounts – give eligible families up to 90 percent of their child’s state education funds each year to pay for tuition to the school of their choice, or to customize their child’s education with a combination of private, public and online instruction.

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Lasko initially set income eligibility requirements for the expansion at 15 percent above the threshold necessary to qualify for free or reduced federal lunch subsidies. State officials complained the eligibility requirement would be too difficult to enforce, so Lasko changed it to include all students in schools with a high proportion of low-income students, according to the news service.

If passed, the legislation would open up the program to about 73 percent, or roughly 880,000, of the state’s students, the Arizona Education Association (the state’s largest teachers union) told the AP.

AEA officials don’t like the voucher program because it allows students to attend nonunionized private and online schools outside of the traditional unionized public school monopoly.

The AEA, which represents employees in most of the state’s public schools, has argued that public funds shouldn’t ultimately end up at private schools, but the association’s real fear is that as more parents choose non-public school options fewer AEA dues-paying members will be needed in public schools.

AEA officials said effort to expand the program as an attempt to shuffle more students away from public schools. They also suggested that the expansion is caused by a lack of parental interest in the original program.

“At this point, not many parents are taking advantage of this program. I think that’s frustrating ESA proponents. They’re trying to accelerate eligibility,” AEA President Andrew Morrill told the AP.

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Then why is the union objecting to the plan? If the program is not popular with families, very few will enroll, even if eligibility is expanded.

Is the union afraid of giving parents a choice?

Lawmakers first approved the ESA program in 2011 for students with disabilities, and expanded it last year to include students in low-performing schools, foster care children and the children of active military parents. Currently, there is an annual 5,000-student cap on new enrollees, which is set to expire in 2019, the wire service reports.

The Arizona House was expected to debate HB 2291 Monday, but delayed action on the legislation.