Republican presidential candidates have not shied away from bashing the Common Core education standards on the campaign trail. Donald Trump promises to "kill Common Core." Ted Cruz has said, "We should repeal every word of Common Core." Marco Rubio promises to "stop the federal government from pushing Common Core on states."

But can the federal government really kill Common Core?

"They can't actually get rid of Common Core," Neal McCluskey, who directs the Center for Educational Freedom at the libertarian Cato Institute, said Saturday at the Conservative Political Action Conference. "The president can't say we're going to eliminate Common Core." It's mostly a state and local issue, not a federal one, although federal overreach led to its adoption.

At this point, the damage is done. A vast majority of states have already adopted Common Core. Most did so before the public furor against the standards began. States were encouraged by federal money in Race to the Top grants and waivers from federal penalties in No Child Left Behind.

Today, the Every Student Succeeds Act has largely killed any chance of the federal government continuing to push Common Core on the states. The bipartisan law was passed in December 2015 to replace No Child Left Behind. The law explicitly forbids the federal government from influencing state adoption of Common Core, and the acting secretary of education has promised to uphold the letter of the law.

There's a chance the Department of Education might use the new law to say anything other than Common Core is unacceptable, but no one knows how likely that is and it also depends on who takes control of the executive branch after President Obama.

So, can the same federal powers that put Common Core into place be used to end it? "Don't look to Washington to get rid of Common Core because it's sort of out of their purview now," McCluskey said.

That puts conservatives and libertarians who oppose Common Core in an awkward position. They can either hope states will take the initiative to get rid of Common Core on their own, or they could attempt to use the heavy hand of the federal government to push states into ditching the standards. The federal approach would go against conservative support for federalism and giving states the power to choose their own policies. It could also be unconstitutional, McCluskey suggested.

Even if it were constitutional, it might not be preferable for conservatives. "What needs to happen is, the states have to step up and reclaim control of education," said Emmett McGroarty, who's the education director of the conservative American Principles Project. He mentioned that federal incentives in Race to the Top used a carrot-and-stick method to influence states. "You don't want the solution to that to be, 'oh, we're going to use the same method to get rid of Common Core.' It would just be a further insult on state decision-making and local decision-making."

Simply put: Federal overreach led to rapid adoption of Common Core. Now it's in the hands of the states. It would be hypocritical to blame federal overreach for Common Core and then use the same tactic to get rid of it. Common Core is out of the federal government's hands now, and for the next president to "kill Common Core" would require more federal overreach.

Jason Russell is a commentary writer for the Washington Examiner.