Ahead of a first-ever statewide walkout on Thursday, some Arizona teachers can’t help but feel a bit worried, with good reason.

A walkout toolkit from the state teachers union warned educators they could be disciplined or fired for walking off the job. Striking could be considered illegal under a decision by the state attorney general, and teachers could lose their teaching credentials, as the Associated Press reported.

Meanwhile, a Republican-backed Colorado bill aimed at pre-empting a teacher walk out in that state would slap striking teachers with potential fines and jail time, as the Denver Post reported.

Add to this the fact that Arizona is a “right-to-work” state with weak unions, and science teacher Gary DeGrow said some teachers are concerned, but pragmatic.

“The threat is there, but for lack of a better term, who are you going to get to fill our position?” questioned DeGrow, who teaches at Perry High School in Gilbert.

Arizona educators last week voted in favor of a statewide strike in reaction to what educators describe as years of school underfunding. Arizona’s per student education spending is one of the nation’s lowest. Nearly one in five public teaching jobs in Arizona remained unfilled at the beginning of the school year, according to a recent survey, and close to 2,500 teaching jobs went to workers without teaching certificates.

“We are actually putting people inside schools who haven’t been formally trained to teach because we can’t find people who want the job,” DeGrow said.

Educators’ decisions to walk out come after weeks of walk-ins—as teachers across the state mobilized behind the grassroots #RedforEd movement—and follows a promise by the state’s Republican governor to raise educator pay 20 percent by 2020. But Arizona educators say they want more than better pay. Their demands include increased education funding, better wages for non-teachers, and a halt to tax cuts until school funding reaches the national average.

Teachers have leveled similar demands in West Virginia, Oklahoma, and Kentucky, with some success.

“I think you’re seeing lot of conservative-leaning red states where tax cuts and underfunding of education have hit a no-turning-back point for educators,” said Josh Buckley, president of the Mesa Education Association.

Arizona, like more than half of states, is a so-called right to work state, where workers can opt out of labor unions, which limits the power of teachers unions to collectively bargain for higher pay and other workplace guarantees. Right-to-work laws are designed to weaken labor unions and tend to lead to lower wages, as NPR reported. Employees in right-to-work states are less likely to have pensions and health coverage through their employers. Right to work legislation has been typically advanced by lawmakers with ties to the anti-union American Legislative Exchange Council.

“Definitely what happened in West Virginia sparked a lot of people to say, ‘OK, a right-to-work state is going on to do it, it’s possible,’”said Buckley, who teaches government and economics to seniors at Red Mountain High School in Mesa.

Since 2009, Arizona legislators have approved $4.6 billion in cuts to public school funding, according to the Arizona School Boards Association. Arizona lawmakers slashed corporate tax rates by 30 percent in 2011, and cut personal income tax rates by 10 percent in 2006, as the Center on Budget and Policy Priorities reported.

Arizona Gov. Doug Ducey (R) told KFIY-FM the state needs to keep taxes low to attract businesses and grow the economy.

Buckley said preparations are underway so teachers, parents, and the community know what to expect on Thursday. He said more than 80 schools in the district where he teaches plan to shut down that day to minimize disruptions. At least 64 school districts and charter school networks have notified parents about plans to close Thursday, as the Arizona Republic reported.

The closures, Buckley said, will help prevent strikers from being singled out for retaliation.

Still, Buckley added, “there’s this little fear in the back of the head that the governor and legislature could come up with something.”

Buckley said educators have paid a price for making public demands. Years ago, after teachers rallied in Phoenix, he said the state lawmakers responded with legislation to get rid of tenure and eliminate payroll deductions for union dues. He said teachers eventually won back the payroll deduction. And this time around, he is optimistic.

“Unless they take aerial photos from the capitol,” he quipped, “it’s going to be really difficult to figure out who walked out and who didn’t.”