PHOENIX — Proponents of a referendum on Arizona’s ambitious school voucher expansion are asking a judge to throw out voucher supporters’ lawsuit challenging the now-scheduled November 2018 public vote.

A dismissal motion filed Tuesday in Maricopa County Superior Court by Save Our Schools argues that the entire lawsuit and many of its specific claims are legally flawed for various reasons.

The lawsuit filed last month by Americans for Prosperity challenged paperwork used in the grassroots signature-collection effort that succeeded in at least temporarily blocking the law.

The law expands eligibility to all students by 2022 but caps enrollment at about 30,000. Eligibility is now limited to categories of students representing a third of all students.

Supporters say vouchers give parents more choice, while opponents argue they divert money from cash-starved public schools.