Pat Quinn just announced that he wants to ban assault weapons and high-capacity magazines in Illinois; as with the handgun ban overturned by McDonald v. Chicago, it's a response to a combination of high-profile shootings and homicide rates:

The conditions that created Chicago’s law have long faded into memory: The city’s ban followed a surge of anti-handgun sentiment triggered by the assassination attempts on President Ronald Reagan and Pope John Paul II in 1981. Proposed by Mayor Jane Byrne and passed in 1982, the city’s ordinance bans the possession of handguns, except for those registered before the law took effect. Morton Grove had passed a similar ban the year before—a first in the nation. At the time, the laws were hailed as commonsense attacks on what newspapers had begun to call the “epidemic” of crime and gun proliferation.

Until recently, the Supreme Court had stayed away from the issue for years: Its position, as written in a 1939 decision, was that the “keep and bear arms” language of the Second Amendment protected only the right of states to raise armed militias.

I wrote about that 1939 case, U.S. v. Miller, at length (Robert Loerzel has more on the history of the machine guns and Illinois gun bans). The gist of Miller is this: it's not okay to ban the weapons that jes'-folks use, but it's okay to ban, or at least tax the crap out of, firearms that bad guys use. That distinction was recognized in Heller, the case that underlies so much of McDonald v. Chicago. As Antonin Scalia wrote for the majority in Heller:

[T]he type of weapon at issue was not eligible for Second Amendment protection:“In the absence of any evidence tending to show that the possession or use of a [short-barreled shotgun] at this time has some reasonable relationship to the preservation or efficiency of a well regulated militia, we cannot say that the Second Amendment guarantees the right to keep and bear such an instrument.” 307 U. S., at 178 (emphasis added). “Certainly,” the Court continued, “it is not within judicial notice that this weapon is any part of the ordinary military equipment or that its use could contribute to the common defense…."

This holding is not only consistent with, but positively suggests, that the Second Amendment confers an individual right to keep and bear arms (though only arms that “have some reasonable relationship to the preservation or efficiency of a well regulated militia”). Had the Court believed that the Second Amendment protects only those serving in the militia, it would have been odd to examine the character of the weapon rather than simply note that the two crooks were not militiamen.

The idea, broadly speaking, is that it's a good idea to have citizenry that possesses and is familiar with firearms in case a militia is needed, not that you can only have arms if you are part of a well-regulated militia:

We think that Miller’s “ordinary military equipment” language must be read in tandem with what comes after: “[O]rdinarily when called for [militia] service [able-bodied] men were expected to appear bearing arms supplied by themselves and of the kind in common use at the time…." The traditional militia was formed from a pool of men bringing arms “in common use at the time” for lawful purposes like self-defense.

Miller is itself something of a compromise: it's good for people to have guns and to be familiar with them in case they are called, but they can't have all the really powerful stuff the military has, just the kinds in "common use." Just in case of, say, secession. It was those sort of able-bodied men with guns that President Lincoln relied upon when the Union faced civil war with an understaffed military, as Adam Goodheart writes in 1861: A Civil War Awakening:

In the entire country east of the Mississippi, the United States Army numbered fewer than four thousand men—several thousand fewer than the rebel forces at Charleston alone. Only a few hundred men defended such places as New York, St. Louis, Baltimore, the mouth of the Chesapeake Bay, and even Washington itself. Most of the national military was stationed in forts along the trails of the Far West and the Pacific coast. In all, the troops totaled just over seventeen thousand enlisted men and officers, many of whom could be expected to defect to the South once hostilities began….

Yet Lincoln, the Sangamon County militiaman, would step decisively into his role as commander-in-chief. This new assertiveness, too, would require him to look beyond War Department memos and official chains of command in Washington. Outside the purview of General Scott, Secretary Cameron, and their assorted file clerks, American citizens in the loyal states were arming themselves—in fact, had been doing so for months. Companies of Wide Awakes that had marched with torches to celebrate the Republican victory in November were now drilling with muskets. And amid the excitement that followed the occupation of Sumter, men throughout the North had formed new militia companies, "putting on their war paint to fight for the Union," as one newspaper had reported back in January. By the end of that month, according to one estimate, nearly half a million had pledged to take up arms against secessionist treason.

If it seems crazy that the right to bear deadly weapons is a response to the remote possibility of fighting off the future Republic of Texas, "the mystic chords of memory" is another way of saying stare decisis.

But armed rebellion isn't the only form of violence that's brought a challenge to Second Amendment law. One of the crucial Supreme Court opinions on the topic arose from the bloody labor conflicts of 19th-century Chicago, Presser v. Illinois, as Stephen Holbrook, who defended the NRA in McDonald (PDF):

[A]n aspiring labor movement, which included many recent immigrants, was beginning to flourish, demanding better working conditions and frightening the members of the economic elite. Working class meetings and demonstrations were increasingly subjected to violent dispersal by police forces and troops. The time had come, the forces of "order" believed, to curtail labor agitation and to restrict public assemblies and the bearing of arms to loyal Americans of the middle and upper classes.

This was not necessarily paranoia. The Illinois National Guard was, at first, privately funded, and its first mission was to protect the establishment from Socialists: "Their target was the upper class-controlled Relief and Aid Society, which had hoarded fire relief funds. The event sent shivers of foreboding through the city's business and civic leaders, who recalled the Paris Commune, a revolutionary upheaval in 1871 that was crushed by the French government with great bloodshed." A militia run by the state and funded by big business set against the common folk is exactly the sort of scenario that piques the interest of Second Amendment absolutists like Halbrook.

Conflict between management and labor continued to increase during the 1870s—the country was struggling through a depression, and Chicago was flooded with laborers who rebuilt the city after the Great Fire—and during the Great Strike of 1877 18 people were killed in four days in the city. It was a violent and dangerous period, and the city's powers that be turned on the laborers; the Chicago Times called for the use of hand grenades against the "uncombed, unwashed mob of gutter-snipes and loafers."

In response, "about 30 German and Bohemian Socialists," reported the New York Times, founded the Lehr und Wehr Verein ("Education and Resistance Association"), "whose object was to train and drill in military fashion and get ready for the great conflict between capital and labor which agitators of that class have for many years declared imminent." In 1879, Herman Presser led the militia through the streets of Chicago, armed with a sword, and was arrested for drilling and parading a paramilitary group without a license, a law passed in response to the rise of labor militias. The Supreme Court, seven years later, upheld Presser's conviction on the basis that only the state can raise a militia, and that fining Presser $10 for leading an unauthorized militia was constitutional.  But it also further outlined the Court's view of the Second Amendment:

It is undoubtedly true that all citizens capable of bearing arms constitute the reserved military force or reserve militia of the United States as well as of the states, and, in view of this prerogative of the general government, as well as of its general powers, the states cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms so as to deprive the United States of their rightful resource for maintaining the public security, and disable the people from performing their duty to the general government.

Presser took up arms a mere decade after the Civil War, and the able-bodied men of the Wide Awakes were still fresh in the mind of the public; as Halbrook writes, "armed parades were hardly radical in that epoch, which was only a decade after Civil War militia units, some of them ethnic or labor based, proudly volunteered and marched through Chicago."

It did not, however, exactly clarify what "keeping and bearing arms" meant, or what "the people" consist of—does the people refer to individuals, or a collective? The answer, according to the Court's decision in Heller, is both: the individual right has to be protected for a collective defense, as the individual ownership of firearms fed into the Union's collective self-defense in the Civil War. At the same time, it narrowed that individual right by curtailing the abilities of individuals to unite for a collective defense outside the state, in contrast to the idea that "a well-regulated body authorized by the government is intended to train itself for action against the government."

How far such regulations can go, and the question of collective versus individual rights to bear arms, are still unsettled, and particularly unsettled in the public. It's well within the powers of the state to crack down on certain classes of weapons, but the direction of the courts has been to limit that regulation before it reaches the individual right to bear (some) arms, in part because the mystic chords of memory still weigh on the Second Amendment.

Photograph: katesheets (CC by 2.0)