On May 10, the Arizona Supreme Court heard oral arguments in a case that could provide a roadmap to eliminate a persistent form of government waste in nearly all 50 states.

At issue is the practice of union release time, which allows government employees paid time off to conduct union activity unrelated to their job duties or any public purpose. The wasteful practice occurs in a majority of state and local governments.

The Goldwater Institute, an Arizona-based free-market think tank, filed a lawsuit in 2011 that argued release time granted to the Phoenix Law Enforcement Association, a government employee union, was an unconstitutional government expenditure.

All told, Phoenix taxpayers were shelling out an estimated $900,000 on an annual basis so law enforcement agents could perform union work instead of protecting citizens. Under the 2010-2012 memorandum of understanding between Phoenix and PLEA, Phoenix police officers conducted thousands of hours of union business — including attending union conferences, lobbying, bargaining over contracts, and participating in grievance procedures — all on the taxpayer dime.

Fortunately, in 2012, the Maricopa County Court concluded that release time is an unconstitutional subsidy to government unions and granted a preliminary injunction on the practice. Arizona's state constitution, along with those of 46 other states, contains a provision known as the Gift Clause, which prohibits use of public funds to the exclusive benefit of private parties.

In Arizona, a two-part analysis is used to determine violations of the Gift Clause: 1) the public must receive proportionate, quantifiable and direct benefit for aid given; and 2) the subsidized activity must primarily serve a public purpose as opposed to private interests.

"Release time provisions do not require that officers in the full-time release positions perform any specific duties," said Judge Catherine Cooper, who struck down release time. "The city's expenditure for the release time was grossly disproportionate to what it received in return, given the lack of obligation imposed on PLEA." She added: "[S]uch activities promote the private interests of PLEA and, as a result, do not constitute public purposes."

In 2015, the Arizona Court of Appeals affirmed the lower court decision. Now the Arizona Supreme Court has a chance to put the issue of whether government unions should be entitled to access taxpayer money in order to fund their activities to rest in the state. If the Arizona Supreme Court establishes release time as unconstitutional, the decision could have far-reaching impact.

The Goldwater Institute, by resuscitating Arizona's gift clause, has pointed the way for citizens across the nation to end government giveaways to special interests like unions, and others are taking note.

In February 2016, the Fairness Center, a Pennsylvania public interest law firm, filed suit against the Allentown School District over the awarding of release time, arguing that the cost of release time to taxpayers — over $1 million since 2003 — violates the state's Gift Clause.

Since 2009, Allentown Education Association President Debra Tretter has exclusively conducted union business and not taught one class. While on the years-long hiatus from teaching, the school district continues to pay her salary, insurance, and benefits, while allowing her to keep her seniority. The lawsuit, filed in the Commonwealth Court of Pennsylvania, is still in its preliminary stages.

Another Gift Clause lawsuit has been filed in the Idaho Fourth Judicial District Court against the Boise Independent School District for paying $35,932 toward the salary of the Boise Education Association president, who doesn't teach any classes. The lawsuit is ongoing with depositions expected in May 2016.

The purpose of the Gift Clause is to protect taxpayers from state and local politicians' tendency to give away the public's money to special interests without receiving anything in return. Union release time is the kind of giveaway that the Gift Clause was meant to shield the taxpayer from. Taxpayers in other states can follow the lead of the Goldwater Institute to end this egregious practice.

Trey Kovacs is a policy analyst with the Competitive Enterprise Institute.Thinking of submitting an op-ed to the Washington Examiner? Be sure to read our guidelines on submissions.