The debate over the Second Amendment has been fierce and terrible, with bad arguments on both sides, and bad will all around. It began in the nineteen-sixties, when there was a great deal of violence and much concern about it. It took another turn on Friday, when, at the N.R.A.’s annual meeting, in St. Louis, Newt Gingrich said, “The Second Amendment is an amendment for all mankind.”

As I wrote in this week’s New Yorker, no amendment received less attention in the courts in the two centuries following the adoption of the Bill of Rights than the Second, except the Third (which dealt with billeting soldiers in private homes). It used to be known as the “lost amendment,” because hardly anyone ever wrote about it. The assertion that the Second Amendment protects a person’s right to own and carry a gun for self-defense, rather than the people’s right to form militias for the common defense, first became a feature of American political and legal discourse in the wake of the Gun Control Act of 1968, and only gained prominence in the nineteen-seventies. A milestone in its development came when Orrin Hatch, serving on Strom Thurmond’s Senate Judiciary Committee, became chair of the Subcommittee on the Constitution. Hatch commissioned a history of the Second Amendment, resulting in a 1982 report, “The Right to Keep and Bear Arms,” which concluded, “What the Subcommittee on the Constitution uncovered was clear—and long lost—proof that the second amendment to our Constitution was intended as an individual right of the American citizen to keep and carry arms in a peaceful manner, for protection of himself, his family, and his freedoms.”

During the nineteen-eighties, this interpretation, which came to be known as the individual-rights argument, gained the attention of several distinguished law-school professors, including, most notably, Sanford Levinson, whose 1989 essay, “The Embarrassing Second Amendment,” was published in the Yale Law Journal. Levinson suggested that legal scholars’ long-standing inattention (“To put it mildly, the Second Amendment is not at the forefront of constitutional discussion,” he remarked), was probably political:

I cannot help but suspect that the best explanation for the absence of the Second Amendment from the legal consciousness of the elite bar, including that component found in the legal academy, is derived from a mixture of sheer opposition to the idea of private ownership of guns and the perhaps subconscious fear that altogether plausible, perhaps even ‘winning,’ interpretations of the Second Amendment would present real hurdles to those of us supporting prohibitory regulation.

Levinson also discussed what is called an insurrectionist interpretation, in which the Second Amendment is thought to allow for a militia of armed citizens standing “ready to defend republican liberty against the depredations” of a government become tyrannical. Levinson didn’t endorse either the individual or insurrectionist views, nor did he dismiss them. Instead, he urged scholars to take them seriously. His essay was essentially a plea for reasoned debate: “Is not, after all, the possibility of serious, engaged discussion about political issues at the heart of what is most attractive in both liberal and republican versions of politics?”

The tragedies at Waco in 1993 and in Oklahoma City in 1995, both of which involved a modern militia movement, brought the insurrectionist interpretation of the Second Amendment to the public’s attention and prompted vigorous critiques. In “To Keep and Bear Arms,” an essay published in The New York Review of Books five months after Timothy McVeigh bombed the Murrah Federal Building, Garry Wills called Levinson’s essay, which had been embraced by the N.R.A., “frivolous,” and reported that he found “a vast outpouring of articles justifying individual gun ownership on the basis of the Second Amendment” to be muddled and tendentious. Wills also noted that, in advancing gun-rights arguments, the same people who offered the individual-rights interpretation usually also endorsed the insurrectionist one. “Only madmen, one would think, can suppose that militias have a constitutional right to levy war against the United States, which is treason by constitutional definition,” Wills wrote. “Yet the body of writers who proclaim themselves at the scholarly center of the Second Amendment’s interpretation say that a well-regulated body authorized by the government is intended to train itself for action against the government.” As to whether those who advocate these positions had been ignored, Wills wrote, “Perhaps it is the quality of their arguments that makes them hard to take seriously.”

In the first decade of the twenty-first century, American historians who disagreed with the individual and insurrectionist interpretations of the Second Amendment began to take them more seriously when it became clear that a conservative judiciary was taking them seriously, and that a test case would reach the Supreme Court. An important statement of what is generally referred to as the collective-rights interpretation—the idea that what the Second Amendment protects is the people’s collective right to keep and bear arms to form militias for the common defense—is an amicus curiae submitted to the U.S. Supreme Court in the 2008 case of District of Columbia v. Heller, signed by fifteen eminent university professors of early American history, including Pauline Maier, Fred Anderson, and Pulitzer Prizes winners Jack Rakove and Alan Taylor. It concludes,