For the Republican Party, the idea of a federal government with limited powers is a lot like a new workout routine: fun to humblebrag about, useful when you need to get out of an obligation, and utterly doomed to failure in the long run. Virtually every Republican on Capitol Hill has sworn to curb federal power, a convenient talking point when the GOP attacks a liberal program like Obamacare. But bring up an issue like marijuana prohibition—which most Republican legislators still support and which relies on strong enforcement from the feds—and the cheers for limited government quickly fade. When you want Congress to stop something you really, really hate, it turns out that supercharged federal power comes in handy.

That’s the lesson to be drawn from congressional Republicans’ latest attempt to ban abortion after 20 weeks, through a bill titled the Pain-Capable Unborn Child Protection Act. If passed and signed into law, the bill would create a nationwide federal prohibition on later-term abortions, criminalizing a procedure that many states have chosen to legalize. Why, exactly, does the self-proclaimed party of limited government think Congress has the constitutional ability to do that? The bill explains:

Congress has authority to extend protection to pain-capable unborn children under the Supreme Court’s Commerce Clause precedents and under the Constitution’s grants of powers to Congress under the Equal Protection, Due Process, and Enforcement Clauses of the Fourteenth Amendment.

Leaving aside the factual problem that 20-week fetuses aren’t actually capable of pain, let’s focus on the bizarre legal reasoning here. Now, the 14th Amendment bars the government from unduly curtailing abortion rights. But imagine, as most Republicans do, that it doesn’t. Were that the case, I would agree that the Commerce Clause—which grants Congress the power “to regulate commerce … among the several states”—could theoretically provide a sufficient basis for Congress to ban abortions. Abortions involve myriad resources that flow through interstate commerce, like drugs and medical devices—and, increasingly, abortions also require transportation across state lines. The procedure is intertwined with commerce among the states. But for the 14th Amendment’s limitations, the Commerce Clause could give the federal government sufficient authority to restrict abortion—or ban it outright.

But this line of reasoning should be utterly anathema to the GOP, which spent the last seven years arguing for a stringently restrained interpretation of the Commerce Clause. The party’s crusade to limit the clause was spurred largely by the Affordable Care Act: From the start, Republicans argued that an individual mandate requiring health insurance coverage was unconstitutional. Their first Obamacare lawsuit centered around the argument that the Commerce Clause could not support the individual mandate, because individual health insurance purchases did not sufficiently implicate interstate commerce. Never mind that health care spending made up nearly 18 percent of the United States’ economy at the time; Congress still didn’t have the authority to make uninsured Americans pay an additional tax on that health care. (The Supreme Court ultimately agreed but upheld the law on taxing power grounds.)

The new anti-abortion bill doesn’t even attempt to explain why the very same clause that wouldn’t be applicable to Congress’ power in health insurance regulation can also be used to effectively override state laws and outlaw abortion. What’s weirder is that the bill does much more than ban later-term abortions; one especially strange provision would let parents sue a doctor who terminated their child’s pregnancy without giving necessary notification. For those keeping score at home: health insurance? Not interstate commerce. Parental notification? Interstate commerce through and through.

As a backup argument, the bill asserts that “the Equal Protection, Due Process, and Enforcement Clauses of the 14th Amendment” also justify its regulations. This argument implies that fetuses should be considered “persons” for the purposes of the 14th Amendment; that abortion deprives these “persons” of life, liberty, and equal protection; and, because Congress has the “power to enforce” these guarantees, it has the power to ban abortions.

Conservatives like Ramesh Ponnuru have struggled mightily to wrangle these presumptions into coherence, which is oddly touching, because they are so clearly ridiculous. I’ll skip the existential debate over whether fetuses can be considered “persons” under the 14th Amendment to save room for a more pressing issue: By its own terms, the amendment applies only to protections against government action. Its critical provisions begin, “No state shall make or enforce any law …” Abortion is not a state action: It is a procedure that involves two private actors, a doctor and a patient. Congress thus cannot lean on the 14th Amendment to pass laws that regulate purely private conduct.

The bill’s gesture toward the Enforcement Clause is also silly given how obviously it contradicts an extensive line of precedents. Congress’ power to enforce the 14th Amendment is limited to remedial legislation designed to preserve an established constitutional right or shield a protected class, like racial minorities, from discrimination.

But under long-standing constitutional jurisprudence, fetuses are not “persons” with a right to life and liberty, nor are they a protected class, a minority in need of extra judicial safeguarding. These judicial determinations bind the legislature; as Justice Anthony Kennedy put it, Congress cannot “enforce a constitutional right by changing what the right is.” Fetuses have no constitutional right to life, liberty, or equal protection. And Congress cannot grant them these rights by directly contravening the Supreme Court.

This tension between the GOP’s two self-images—as the party of limited government and the party of abortion bans—doesn’t seem to bother most Republican legislators, who can write off the contradiction by insisting that fetal lives need protection. But what about the GOP’s devotion to a limited federal government? This plank of the platform has become even more critical to the party’s identity in the Obama era. And yet congressional Republicans have consistently prioritized anti-abortion bills that would push federal power to unprecedented heights. Bringing Congress to a heel sounds nice on the campaign trail. But when it comes to banning abortion, or outlawing marijuana, or prohibiting same-sex marriage, all that talk is about as cheap as it gets.