As my colleague Anna Giaritelli notes, gun control activists are calling for U.S. adoption of New Zealand's new gun regulations, as ordered by Prime Minister Jacinda Ardern following last week's terrorist attack.

One problem: these calls reflect either a basic lack of understanding on U.S. constitutional law, or a failure to actually read the New Zealand regulations.

I have read those regulations, and I am convinced that Ardern's new regulations would be patently unconstitutional were any federal, state, or local government to enact them in America.

Section 3. of the Order (effectively clarifying legislation for New Zealand's 1983 Arms Act) rules that most semi-automatic firearms are now to be regarded as "military-style weapons." The order declares that illegal firearms will now include:

[A] semi-automatic firearm that is capable of being used in combination with a detachable magazine (other than one designed to hold 0.22-inch or less rimfire cartridges) that is capable of holding more than 5 cartridges [and] a semi-automatic firearm that is a shotgun and that is capable of being used in combination with a detachable magazine that is capable of holding more than 5 cartridges.

Five cartridges means five rounds. And "a semi-automatic firearm that is capable of being used in combination with a detachable magazine," means the vast majority of handguns relied upon by Americans to protect their families and homes.

This is the key issue. Such a ban in America would explicitly conflict with the Supreme Court's ruling in the most relevant Second Amendment case, District of Colombia v. Heller. And don't take my word for it — read Antonin Scalia's rationale for why most semi-automatic handguns used to defend American homes are constitutionally protected: "There are many reasons that a citizen may prefer a handgun for home defense: It is easier to store in a location that is readily accessible in an emergency; it cannot easily be redirected or wrestled away by an attacker; it is easier to use for those without the upper-body strength to lift and aim a long gun; it can be pointed at a burglar with one hand while the other hand dials the police. Whatever the reason, handguns are the most popular weapon chosen by Americans for self-defense in the home, and a complete prohibition of their use is invalid."

This, the Supreme Court concluded, means that when it comes to comparing the First Amendment to the Second Amendment: "The Second Amendment is no different. Like the First, it is the very product of an interest-balancing by the people... And whatever else it leaves to future evaluation, it surely elevates above all other interests the right of law-abiding, responsible citizens to use arms in defense of hearth and home."

Yes, the Supreme Court has declined to overrule state regulations banning firearm magazines with capacities of more than ten rounds. But Heller's finding of a basic right to self-defense via semi-automatic handguns would proscribe a six round or more magazine capacity limit as unconstitutional. After all, that limit would effectively ban possession of any handgun. Indeed, that is why state magazine capacity bans are focused on a ten round limit: restrictions at a lower-round number such as five rounds would effectively ban handguns and thus invite the Supreme Court to overrule them.

There's another point that stands out from Heller: its imperative that individuals be able to defend their homes effectively. Considering that trained police officers in firearms incidents miss their targets more often than they hit them, a magazine capacity limit of five rounds would degrade the right of self defense to a level of impotency.

This is not ultimately a question of opinion.

We all have our views on the Second Amendment and gun rights. Yet, when it comes to judging New Zealand's legislation as applied to U.S. constitutional rights, the law stands clear. In the American Left's salutation of this legislation, we're seeing another example of gun control conversations driven by a lack of understanding and European-style emotional response.