The teacher strike enters its third day today as educators remain dissatisfied with the pay hike proposal by Gov. Doug Ducey and many schools remain closed despite threats by the Goldwater Institute to sue.

Timothy Sandefur, an attorney for the organization that litigates over conservative causes, contends the walkout by teachers that has affected close to 850,000 youngsters statewide is an illegal strike.

“Public school teachers in Arizona have no legal right to strike, and their contracts require that they report to work as they agreed,” he said.

But the real target of his legal threats are individual school districts who he contends are facilitating that illegal activity. That includes everything from closing schools while the teachers and support staff are staying away to refusing to dock the pay of the absent teachers.

The bottom line, Sandefur said, is that not only makes school officials equally guilty of an illegal act but puts them in violation of their constitutional obligations to educate children.

“In order to prevent the possibility of a lawsuit, it is necessary for district employees to return to work, and for the district to operate as normal, including, if necessary, taking steps to find substitute teachers to replace those who refuse to comply with their legal and contractual obligations,” he wrote in identical letters to school districts around the state.

So far, though, the majority of those districts that closed their schools starting April 26 have shown no signs of reversing course, at least for the moment.

In fact, Tim Ogle, executive director of the Arizona School Boards Association, said the local board members who have made these decisions are doing the only legally defensible thing. He told Capitol Media Services it would be “irresponsible” to open a school building after administration determines there would not be enough staff to safely supervise the students, much less actually try to conduct lessons.

Sandefur doesn’t see it quite that way.

He said it would be one thing if a school were closed for a “genuine public safety reason.” This, he said, is not that.

“Districts have encouraged teachers not to show up for work,” Sandefur said. And he said they have an obligation to seek out substitutes.

But Joe Thomas, president of the Arizona Education Association, said there is no constitutional violation.

“Districts are free to set their own calendars,” he said, just so long as they provide the minimum hours of instruction required by state law. And if that means altering the calendar to add a few extra days at the end of the school year, that’s perfectly legal.

But Thomas’ organization is doing more than spouting philosophy.

It has fired off its own letter to Attorney General Mark Brnovich challenging Sandefur’s claims that teachers are acting illegally. It also seeks to debunk a parallel argument by state schools chief Diane Douglas that the teachers have abandoned their jobs, meaning their teaching certificates can be suspended or revoked by the state Board of Education.

Jarrett Haskovec, the AEA’s general counsel, said it is up to each school district and not Douglas nor the state board to determine if a teacher has effectively resigned.

But the bigger issue — and one central to whether teachers and school districts face liability — is the question of whether teachers are “on strike.”

There is some legal precedent to suggest public employee strikes are illegal. But Haskovec said the problem with that argument is it doesn’t apply here, saying that strikes are job actions taken by workers to compel an action by their employer.

“Instead, teachers are engaging in a walkout as a form of protest and as petitioning activity,” he wrote to Brnovich. “Teachers are not seeking concessions from school districts, but rather are seeking to create public awareness of the dire condition of public school funding and to demand action and a remedy from the state Legislature and the governor.”

Sandefur, however, told Capitol Media Services he does not define the word “strike” quite so narrowly, citing the General Strike of 1926 in Great Britain by labor groups seeking to pressure the government over issues of wages and labor conditions.

But the question of whether teachers are striking when they don’t show up at schools gets even trickier.

Many teachers who have not shown up at school are using “personal days,” something they are entitled to in their contracts. And even Sandefur acknowledged that teachers are, in fact, entitled to personal days and even sick days.

But he said it’s quite something else if districts changed their policies to accommodate the walkout. Sandefur even claimed that one school district — he did not identify which — changed its policy on a Sunday evening to allow teachers to call in “sick” without a doctor’s note.

Even if true, however, that might not be illegal.

The 2016 law that boosted the minimum wage to $10 an hour — it’s now $10.50 — also contains a provision guaranteeing all employees paid time off for sick leave. More to the point, it spells out that employers can demand “reasonable documentation” of a legitimate use of that time off only if the worker takes off three or more consecutive days.

And while Gov. Doug Ducey has urged teachers to return to the classroom, he is not a supporter of resolving the issue in court.

“We are interested in solutions, not lawsuits,” press aide Daniel Scarpinato said Sunday.

Ducey has reached a deal, not with educators but with Republican lawmakers, to boost teacher pay by 19 percent by the 2020-2021 school year, though the plan gives individual school districts some flexibility on how to divide up the funds.

Both the Arizona Education Association and Arizona Educators United remain dissatisfied, at least in part because there is no dedicated funding source to guarantee the funds will be there. They also say the plan has no funds earmarked for support staff and ignores their request to restore per-student funding to where it was a decade ago.

The teacher strike, the largest both in the nation and Arizona’s history, is commanding national attention, with Randi Weingarten, the president of the American Federation of Teachers, at tge Capitol today to speak at a rally.