The future of Common Core is in doubt. In the reddest states—places like Alabama and Oklahoma—legislators are vowing to dismantle it entirely. In less staunchly conservative states (Indiana, Wisconsin), legislators have “pressed pause.” In New York state, hardly a Republican stronghold, parents and educators are angry over preliminary results.

The Common Core State Standards, a K-12 overhaul that’s been adopted by 45 states over the past few years, has enemies of every political persuasion. But the current outrage is strongest among conservatives, who view Common Core as a top-down mandate from the Obama administration. (In fact, the voluntary standards were developed by the National Governors Association and the Council of Chief State School Officers. But the White House has tacitly endorsed the reforms, mandating that states have “college and career ready standards” in order to receive federal grants. The federal government has also bankrolled the development of tests that align with Common Core.)

Full implementation of the new standards is set for this fall. But the vitriol over Common Core could undermine the program well before then.

Changes to curricula are the purview of state education boards, so legislatures were largely uninvolved when states adopted the new standards. But as schools have begun putting the standards in place, the backlash has grown fierce. Last year, about 20 bills revoking the standards floated around statehouses. Not one was successful. But efforts to press pause—suspending implementation to hold public hearings and reviews—were passed in Indiana, Michigan and Wisconsin. (Michigan has since voted to restore Common Core.)

The Republican rancor isn’t uniform. Conservatives oppose the plan while more moderate members of the GOP support the standards as part of a broader effort to inject greater accountability in schools. Democrats, meanwhile, aren’t universally supportive: Some liberals don’t like the idea of linking teacher evaluations to student achievement.

What does that mean for this year? Some states will no doubt debate bills to completely reject the Common Core standards they’ve already adopted. But it’s more likely, education scholars say, that more states will develop their own tests rather than use the ones backed by the federal government. Georgia and Oklahoma have both decided to write their own tests, citing issues of cost and control. Other states, including Louisiana and Massachusetts, have delayed linking test results to accountability requirements for students and teachers.

That’s a fight that’s far from over, says Tom Loveless, a fellow at the Brookings Institution, who predicts more states will follow Georgia and Oklahoma’s lead. “I think the sternest opposition is yet to come.”