After 51 Muslim worshipers were gunned down in Christchurch, New Zealand, the country’s parliament swiftly moved to ban military-style semiautomatic weapons, assault rifles and high-capacity magazines, and then introduced an ambitious buy-back program. Now Joe Biden has announced that as president he would do what few political leaders have dared to consider – permanently reinstate the ban on assault-style weapons that was in place across the nation from 1994 until 2004.

Whether Biden – or any president – could succeed in pushing through such a measure remains highly doubtful. But even assuming a herculean exercise of political will, it is far from clear that such a ban could survive review by the supreme court. That is the shocking upshot of the court’s radically new second amendment jurisprudence.

From 1791 until 2008, the supreme court refused to touch gun-control laws. True, the second amendment spoke of a right to bear arms, but it did so in conditional fashion: “A well-regulated Militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed.” The roundabout formulation was striking: the constitution does not limit other rights – such as freedom of speech – to any particular purpose or function.

Attentive to this language, the supreme court long interpreted the second amendment as protecting a collective right to participate in a militia. In 1939, the court unanimously upheld a congressional ban on sawed-off shotguns, arguing such weapons lack “any reasonable relation to the preservation or efficiency of a well-regulated militia”.

All that changed in 2008 with the court’s 5-4 decision in District of Columbia v Heller. In striking down a Washington DC ban on handguns in the home, the court’s conservative majority held for the first time that the second amendment “protects an individual right to possess a firearm unconnected with service in a militia”.

Relying on an “originalist” reading of the constitution, Justice Antonin Scalia insisted the supreme court had essentially misread the second amendment for 200 years. Originalists claim that reading the constitution as understood at the time of its adoption makes a judge a more faithful interpreter of constitutional text, although in reality this approach guarantees no such thing. To the contrary, it permits judges to cherry-pick history to reach virtually any outcome, or, as in this case, to radically overturn decades of received wisdom in the name of constitutional “fidelity”.

Not all constitutional rights are created equal. The fifth amendment, for example, guarantees a right to grand jury indictment in federal criminal trials, but the supreme court long ago concluded that because the right was not fundamental, it did not bind state courts. Freedom of speech, by contrast, is a fundamental constitutional right, and so both state and federal governments are limited in their power to regulate speech.

In the wake of Heller, the court left open the question – is the individual right of gun ownership more like the right to a grand jury indictment, or more like the fundamental right to free speech? In McDonald v Chicago (2010), a similarly divided court gave its fateful answer. “It is clear,” Justice Samuel Alito wrote, “that the Framers and ratifiers … counted the right to keep and bear arms among those fundamental rights necessary to our system of ordered liberty”.

In elevating gun ownership into a fundamental individual right, the court has erected a formidable constitutional barrier to shaping a sensible political solution to a horrific national problem.

To appreciate the bizarre and dangerous consequences of this blinkered doctrine, consider a recent opinion by Justice Clarence Thomas. Last year, the supreme court chose not to review California’s 10-day waiting period for firearm sales. This prompted Justice Thomas to accuse his colleagues of turning the second amendment into a “disfavored right” – a veritable “constitutional orphan”. Thomas’s argument – that the court should subject any state regulation of gun rights to the same exacting scrutiny that it would devote to regulating free speech – is at once frightening and abhorrent. Yet it is also the logical conclusion of the court’s ruling in McDonald.

No less troubling is an opinion that Justice Brett Kavanaugh wrote during his tenure as a judge on DC’s federal appellate court. Applying the court’s reasoning in Heller, Kavanaugh argued that any ban on semiautomatic rifles should be struck down as unconstitutional.

That bears repeating: A ban on semiautomatic weapons would be unconstitutional. Using “text, history, and tradition” as his guides, Kavanaugh concluded that semiautomatic rifles “have not traditionally been banned and are in common use by law-abiding citizens for self-defense in the home, hunting, and other lawful uses”.

Why does the fact that we’ve permitted such weapons in the past mean that we are constitutionally tethered to them now? The logic again follows straight from the disastrous Heller ruling.

Perhaps worst of all, Heller dramatically and dangerously altered the rhetorical stakes in the battle over gun control. For decades, gun zealots ranted about an individual right to gun ownership. In Heller, the supreme court mainstreamed a radical outlier position into constitutional doctrine. Two centuries ago, the great English philosopher Jeremy Bentham warned of the danger of permitting a rhetoric of rights to hijack what really are and should be policy arguments. Is this not “putting into the hands of every fanatic arms that he can use against all governments?” Bentham asked.

Yet this is precisely what the court has done in Heller and McDonald. And all too literally.