Gun rights advocates have sketched out arguments they hope will convince the U.S. Supreme Court that no state can be a Second Amendment-free zone.

In a 73-page legal brief filed on Monday, the groups representing four Chicago residents asked the Supreme Court to overturn the city's extremely restrictive firearms laws, some of the most severe in the nation.

"It is unfathomable that the states are constitutionally limited in their regulation of medical decisions or intimate relations, because these matters touch upon personal autonomy, but are unrestrained in their ability to trample upon the enumerated right to arms designed to enable self-preservation," says the brief, written by attorneys Alan Gura of Alexandria, Va. and David Sigale of Lisle, Ill. on behalf of the Second Amendment Foundation.

Translation: Even though abortion is not mentioned anywhere in the U.S. Constitution, courts have nevertheless declared it to be a fundamental right. Shouldn't the Second Amendment, which originally was requested by more states than the First Amendment was, receive at least equal treatment?

Much of the brief -- the vast majority, in fact -- reads more like a history textbook than appellate writing. Gura and his co-counsel use that space to recount, in exhaustive detail, how the post-Civil War measure called the Fourteenth Amendment was designed to protect anyone's fundamental rights from being infringed by state governments. Their argument, which I wrote about last month, traces the Fourteenth Amendment's "privileges or immunities" concept through American history and offers contemporaneous evidence that it protects gun rights against infringements by states and municipalities.

Some background: the Second Amendment, of course, says that Americans' right to "keep and bear arms" shall not be infringed. Last year's decision in D.C. v. Heller applied that prohibition only to the federal government and federal enclaves like Washington, D.C., but left open the question of "incorporation" -- that is, what state laws were permissible or not.

As a result, in the wake of Heller, anti-gun court decisions have proliferated. There's the Maryland appeals court that concluded residents enjoy no constitutional gun rights (Maryland's constitution is silent on the topic), a similar New Jersey ruling, and another one from Illinois.

Because the Supreme Court already has specified that the Second Amendment protects an individual right, the current case will center on the original meaning of the Fourteenth Amendment. Stephen Halbrook, a lawyer and historian who has written a book titled Freedmen, the Fourteenth Amendment, and the Right to Bear Arms, has reviewed the debate in the U.S. Congress over extending the right to bear arms to the newly-freed slaves after the Civil War. He concludes: "The framers of that amendment understood from hard experience that the rights to personal security and personal liberty are inseparable from the rights to self defense and to keep and bear arms."

At some level, gun rights are like abortion rights: Every justice likely has an opinion on the Second Amendment, meaning attorneys for the city of Chicago and the Second Amendment Foundation won't be persuading as much as offering arguments that members of the court can adopt as their own. (Justice Sonia Sotomayor appears to hold the same not-very-gun-friendly position as David Souter, whom she replaced.)

Neither side expects a revolutionary outcome. Laws barring felons and the mentally ill from owning firearms will stay on the books. The majority opinion won't emphasize a constitutional right to manufacture or purchase fully-automatic weapons.

But those are examples on the extremes, and many state and local ordinances target law-abiding gun owners planning to buy something less powerful than, say, a Solothurn S-18/1000 anti-tank gun. Which laws will stand, and which won't? Assuming that the justices agree that the Second Amendment applies to states, the most important sentence from the opinion will be the one instructing lower courts on where, exactly, to draw the line.