Since the start of the new year, anti-choice state legislators have introduced bills to abolish abortion in their states by invalidating—or nullifying—federal law. If the decades since Roe v. Wade were about chiseling away at abortion access, these bills are now going for the jugular.

Meanwhile, some Republican lawmakers are attempting to criminalize abortion in their states—domestic terrorist Washington Rep. Matt Shea (R-Spokane Valley) and Idaho Rep. Heather Scott (R-Blanchard), who has defended white nationalists, are trying for the second time—by combining fetal personhood with the Confederate-era theory of nullification.

Bills like HB 2154 in Washington, HB 1089 in Indiana, HB 361 in Idaho, SB 13 in Oklahoma, and HB 1075 in Colorado have all been introduced in the first 60 days of this year seeking to override Roe. These nullification bills can look like pure political theater as they have little legal foundation—but they’re actually deviously clever. Because neither access to abortion nor a definition of life is explicitly referenced in the U.S. Constitution or federal law, the sponsors of these bills make their case that states have the power to legislate both, per the Tenth Amendment‘s granting of state authority.

Nullification as a tactic is not new. David S. Cohen, an associate professor at Drexel University and a gender and constitutional law expert who’s contributed to Rewire.News, said that Republican lawmakers who have proposed these recent bills are “keeping the company of the worst in this country’s history in terms of slavery and segregation.”

As far back as the Founding Fathers, state lawmakers have fought for states’ rights to decide what is constitutionally valid within their state’s borders. States have largely relied on nullification to uphold white supremacist and patriarchal systems. Leading up to the Civil War, Southern state lawmakers used the argument of nullification to try to kick Native Americans off their land, to refuse to enforce federal tariffs, and secede from the Union. Southern states also used the nullification argument in the wake of Brown v. Board of Education in an attempt to avoid racially integrating schools.

So how did these tactics make a comeback? Over the past decade, alongside the rise of the Tea Party movement, nullification enthusiasts have organized in states’ rights groups like the Tenth Amendment Center (TAC), as well as far-right extremist groups like Oath Keepers. Since its formation in 2007, TAC has emerged as the thought leader on modern-day applications of nullification. The group’s model legislation has informed recent nullification bills, like those introduced during the multistate legislative campaign to reject the Affordable Care Act, and the ongoing wave of bills to thwart federal gun regulations.

For these self-described tenthers, nullification acts as a cudgel against any federal law they don’t want to uphold, judicial review and federal supremacy be damned.

To apply nullification to abortion regulations, state lawmakers have to get around the fact that the U.S. Supreme Court ruled access to abortion as a constitutional right with Roe v. Wade.

Each of the five bills introduced this year do so in the following ways:

1. assert that states have a compelling interest in protecting a fetus;
2. provide that life begins at conception;
3. make a Tenth Amendment claim to deem any federal law that contradicts what is written in the bill as “null, void, and unenforceable”; and
4. provide some sort of threat of retaliation should the federal government choose to enforce federal law in those states.

“It’s a really important strategy for them,” said Jessica Mason Pieklo, Rewire.News‘ vice president of law and the courts. “In order to get around abortion rights precedent, these bills have to do a few things… They have to clearly assert a source of state power, [show that the state] has a compelling interest [in passing the law], and that the restriction has to substantially further that compelling interest… and still pass that undue burden test.”

The level of constitutional scrutiny for abortion regulations has been whittled down from “strict scrutiny” in Roe, to “compelling scrutiny” and an “undue burden” test in Planned Parenthood v. Casey and then Whole Woman’s Health v. Hellerstedt. By using the nullification language and asserting Tenth Amendment authority, “these laws are trying to … restart that conversation and change the terms of it,” Mason Pieklo said. Under these new terms, “abortion isn’t a fundamental right, so states only need a rational basis—not a compelling interest—to legislate around it. The point of these laws is to say … the federal laws don’t apply here,” she added.

Yasmine Ergas, director of the gender and public policy specialization at Columbia University, described the novelty of these bills: “In the third trimester, there’s a compelling state interest in the life of the fetus. But that trimester framework gets changed in Casey. Nonetheless, women’s rights are predominant,” and the undue burden test, if applied to these bills, would remain the same, “although what [these bills are] saying is, ‘We don’t care about your test.’”

Even if state lawmakers concede that their bills are in fact subject to the constitutional scrutiny determined by the Court, they maintain they “have a compelling interest in litigating on behalf of the unborn,” according to Pieklo Mason.

But how can a state assert a compelling interest in protecting a fetus under the 14th Amendment when neither the Court nor federal law has agreed that a fertilized egg is a person? Nullification, of course.

While anti-choice lawmakers have long claimed that they must protect the inalienable rights of the fetus from the time of conception via fetal personhood bills, tenthers assert that state lawmakers get to define what constitutes a “person.”

Oklahoma’s SB 13 states that “a living human child, from the moment of fertilization… is entitled to the same rights, powers, privileges, justice and protections as … any other human person.” Idaho’s HB 361 aims to make abortion illegal, “regardless of any contrary or conflicting federal statutes, regulations, executive orders, or court decisions.”

Sometimes, the bills go even further and criminalize people who infringe on the rights of fetuses they deem as people. Indiana’s HB 1089 goes as far as to threaten federal agents who enforce the Constitution within Indiana’s borders: “A federal officer or agent who arrests any Indiana government official for compliance with this article … shall be subject to arrest by Indiana law enforcement.”

We have already seen states criminalize pregnant people—disproportionately women of color—who experience pregnancy loss. State lawmakers who want to use nullification and fetal personhood to ban abortion want to prioritize the rights of a fertilized egg over the pregnant person carrying it.

“Women have a right to life, and a right to health … doesn’t life imply a certain amount of health?” Ergas said. “Certainly life is not simply a positive heartbeat.”

If these bills became law, the only recourse for pregnant people would be federal law enforcement intervention, which is exceedingly unlikely given the current state of our federal executive and judicial branches.