The relentless string of teachers’ walkouts continued on Tuesday in West Virginia, where educators held the second statewide walkout in less than a year, denouncing a bill that they said was retaliatory toward educators.

Hours later, their action, which shut down schools in all but one of the state’s 55 counties, led to a victory. The state House of Delegates voted to indefinitely table the bill, which would have allowed tax dollars to pay for private school tuition and established charter schools in the state for the first time. Still, union leaders said the walkout would continue on Tuesday, to ensure Republicans in the state Senate would not attempt to revive the measure.

“There’s no trust,” said Jay O’Neal, a West Virginia teacher and walkout leader. “We want to make sure they don’t do something shady tomorrow morning.”

West Virginia educators kicked off the teacher protest movement almost exactly a year ago, winning a raise from lawmakers after a nine-day walkout. This week, education unions in the state called for a walkout on Monday night and were able to immediately mobilize workers and extract concessions from lawmakers, pointing to their powerful and enduring influence as a political force — despite laws in the state that weaken labor unions.

The next battleground for educators will be in California, which is bracing for a districtwide strike in Oakland on Thursday.

The teachers’ movement started with cries for better pay and benefits for educators, and more funding for schools and classrooms. It has evolved into a revolt against the argument that has driven the bipartisan education reform agenda for the past two decades: that traditional public schools and the people who work in them are failing, and that they must be challenged by charter schools, private school vouchers, test-driven accountability and other forms of pressure to improve.

Here’s the latest on the teacher walkouts:

Why do teachers keep striking?

The teacher protest movement began in the run-up to the 2018 midterm elections. Educators in six conservative and swing states with weak unions — West Virginia, Kentucky, Oklahoma, Arizona, Colorado and North Carolina — thronged capitals to demand that politicians raise education budgets, sometimes by instituting new taxes.

Those protests won teachers a series of modest raises, but were less successful in pushing back against fiscal austerity more broadly. And though candidates who supported the walkouts won some state-level elections in November, the movement was not able to flip party control in red bastions like Arizona and West Virginia. That’s the major reason some of the same fights over local school funding, salaries and reform policies are still going on.

How has the movement changed?

The movement has entered a second phase, which began at the end of 2018. Teachers led by strong unions organized strikes in a series of liberal cities. Those actions took place in Chicago charter schools and in Los Angeles, Denver and now Oakland.

The protest is no longer solely against the types of policies, like tax cuts and trimming budgets, that Republicans tend to support. With teachers pushing back against charter schools and other forms of school choice and competition embraced by some Democrats, the movement has taken on new life and may continue to spread.

Why are teachers protesting the West Virginia bill?

The bill that teachers pushed back against, championed by Republican state Senate leader Mitch Carmichael, would have established seven charter schools and 1,000 education savings accounts, which allow taxpayer dollars to pay for private school tuition. It would have also given teachers and other school workers a 5 percent raise, in addition to the 5 percent raise they won with last year’s walkout.

But organizers said getting a raise was less important than taking a stance against what they call school privatization. (Charter schools are publicly funded but privately managed.) They saw the state Senate’s action as retaliatory against their movement, and expect to push for a separate teacher pay bill in the coming weeks.

What’s happening in California?

Several thousand teachers in Oakland expect to strike Thursday. The district has about 36,000 students, and the teachers union is pushing back against a proposal to shut down dozens of schools that serve predominantly black and Latino students. They are also asking for a raise, more charter school accountability and more funding for guidance counselors and nurses.

The Oakland Unified School District says it may be necessary to close schools because of a budget shortfall and declining enrollment. Families are leaving Oakland for the same reason teachers are dissatisfied with their pay: the Bay Area’s staggering housing costs, driven by the growth of the technology sector and a lack of new construction.

These issues are similar to those that prompted a weeklong strike in Los Angeles last month. That strike ended with the school board moving to slow the growth of the charter school sector.

This article originally appeared in The New York Times.