On Tuesday, the Chicago-based 7th Circuit Court of Appeals struck down Illinois’s ban on carrying ready-to-use firearms. Moore v. Madigan is written by Judge Richard Posner, possibly the most famous non-Supreme Court judge in the country, and is an important extension of the Second Amendment right to keep and bear arms. Judge Posner’s decision makes it very clear that the right to self-defense entails more than just allowing people to keep guns in the home.

In the landmark case of United States v. Heller, a case in which Cato was intimately involved, the Supreme Court struck down the District of Columbia’s near total-ban on having guns in the home. Two years later, in McDonald v. Chicago, the Court expanded this protection to the states, striking down Chicago’s equally draconian gun ban.

Ever since those two cases established and expanded the right to keep and bear arms, lawyers have been testing the waters to see how far the Supreme Court’s ruling goes. Heller held that the protection of the home with a reasonable firearm (i.e. a handgun, not a rocket launcher) is the core of the Second Amendment. While that right cannot be totally eliminated by states and municipalities, it is still subject to reasonable regulation. Yet this holding only addressed the Second Amendment right to keep arms, not to bear them. Both words are in the Amendment and both words clearly mean different things.

Up until Tuesday, Illinois was the last state to flatly ban all carrying of ready-to-use guns outside the home. Since the mid-1980s there has been a remarkable proliferation of states that offer concealed-carry permits. As you can see from this nifty animation, in 1986 only 34 states allowed their citizens to carry guns. Moreover, most of those states had “may-issue” permitting, meaning that local officials are given broad discretion in choosing who gets a permit. “May-issue” statutes often contain discretionary language such as, “if the sheriff determines the applicant to be of good moral character and of having proper cause for wanting a permit then he may issue a permit.” While “may-issue” laws are better than “no-issue” laws, they imbue local officials with far too much discretion over whether a citizen is of sufficient “moral character” and has “proper cause” to be allowed to exercise her fundamental right to self-defense. In a decision that Judge Posner criticizes in Moore, the Second Circuit recently upheld New York’s “proper cause” provision.

As you can tell by the animation, the growth in “shall-issue” states is astounding. Today, unless you live in Illinois, you may be surrounded by many legally gun-toting citizens, and while you may not have noticed this, trust me, the criminals have. And despite this massive increase in the legal carrying of weapons, crime is still going down and we are not living in a modern recreation of the Wild West. Instead, as Clayton Cramer and David Burnett documented in the recent Cato study, Tough Targets, those carrying weapons are increasingly using them to protect themselves and to save lives.

In his decision, Judge Posner discusses the evidence on both sides of the debate over the relationship between guns and crime. He also decides that the evidence is more or less irrelevant to the question of whether the Illinois ban can survive:

In sum, the empirical literature on the effects of allowing the carriage of guns in public fails to establish a pragmatic defense of the Illinois law. Anyway the Supreme Court made clear in Heller that it wasn’t going to make the right to bear arms depend on casualty counts. If the mere possibility that allowing guns to be carried in public would increase the crime or death rates sufficed to justify a ban, Heller would have been decided the other way, for that possibility was as great in the District of Columbia as it is in Illinois.

Posner then finds the Illinois ban squarely proscribed by the plain language in Heller and McDonald:

A woman who is being stalked or has obtained a protective order against a violent ex-husband is more vulnerable to being attacked while walking to or from her home than when inside. She has a stronger self-defense claim to be allowed to carry a gun in public than the resident of a fancy apartment building (complete with doorman) has a claim to sleep with a loaded gun under her mattress. But Illinois wants to deny the former claim, while compelled by McDonald to honor the latter. That creates an arbitrary difference. To confine the right to be armed to the home is to divorce the Second Amendment from the right of self-defense described in Heller and McDonald.

The decision is certainly an important victory for the right to self-defense. We will now wait to see if Illinois appeals the decision. While Judge Posner struck the ban down, he delayed his mandate for 180 days in order to “allow the Illinois legislature to craft a new gun law that will impose reasonable limitations, consistent with the public safety and the Second Amendment as interpreted in this opinion, on the carrying of guns in public.”

My prediction is that, rather than risk the Supreme Court affirming the ruling, Illinois will impose a severely limited permitting system. Either way, this is certainly the most important case decided under the Second Amendment since McDonald.