The District argues in its petition for review that its law--one of the toughest handgun bans in the nation--should be upheld regardless of whether the court sides with the so-called "individualist" or "collective" legal theories.

"It is eminently reasonable to permit private ownership of other types of weapons, including shotguns and rifles, but ban the easily concealed and uniquely dangerous modern handgun," states the petition, filed by District Attorney General Linda Singer. It adds: "Whatever right the Second Amendment guarantees, it does not require the District to stand by while its citizens die."

"We're going to fight to uphold a law that . . . has public support," Mayor Adrian M. Fenty (D) said at a news conference outside D.C. police headquarters. "The only possible outcome of more handguns in the home is more violence. Our appeal will help the District of Columbia be able to continue to reduce gun violence."

A three-judge panel of the U.S. Court of Appeals for the D.C. Circuit split 2-1 last March in throwing out the District's law, which prohibits handgun ownership except by active and retired law enforcement officers. It also struck down a law requiring that rifles and shotguns kept in private homes be unloaded and disassembled or bound by trigger locks.

The court ruled that the Second Amendment "protects an individual right to keep and bear arms" and that "once it is determined--as we have done--that handguns are 'Arms' referred to in the Second Amendment, it is not open to the District to ban them."

The appeals court acknowledged that its decision was groundbreaking; only one other appeals court--the Fifth Circuit based in New Orleans--has recognized an individual's right to gun ownership, and it nevertheless upheld the federal gun-control law at issue. Nine other circuits around the country have endorsed the "collective" right.

That split is what makes it likely the justices will accept the case, and the lawyers who brought the case on behalf of six District residents who wanted to overturn the gun ban also want the court to take the case.

"We support the court granting [review] and plan on responding very quickly," said attorney Alan Gura, one of the lawyers who brought the case.

Singer said the city expects to hear by November whether the high court will hear the case. The District would be represented in court arguments by Alan B. Morrison, special counsel to Singer's office.

"This is more than an intellectual or ideological argument. It's real," Singer said. "For the residents of the District of Columbia, it's a matter of life and death."

The Supreme Court has not specifically addressed the gun rights guarantees of the Second Amendment since 1939, when it upheld a federal gun control law and seemed to side with the "collective" right argument.

The Second Amendment provides: "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms shall not be infringed."

The appeals court's decision to focus on "the right of the people to keep and bear Arms shall not be infringed"rather than "A well regulated Militia, being necessary to the security of a free State'' reflects a growing trend in the legal and academic community.

So while the District argues in its petition that the appeals court decision ignored the "obvious military character" of the Second Amendment's language, it spends more time making the case that its law should be upheld even if a majority of the justices embrace the individual rights theory.

Its legal filing contends that the Second Amendment was meant to protect the states from federal intervention, not to restrict their legislative decisions. "States remain free to regulate arms within their boundaries so long as they do not thereby deprive the United States of the ability to obtain the assistance of an armed citizenry in time of need," the petition states.

And the petition says the high court should recognize that banning handguns, which it calls the criminal's "weapon of choice," was a reasonable response in an urban area marked by high crime rates.

District lawyers argue that the ability to own shotguns and rifles satisfied the desire of the law's challengers for a means of self-protection. The appeals court found that argument "frivolous."

The petition also includes a long list of statistics it says bolsters its claims that the availability of handguns increases the number of suicides and endangers children and police officers. "No other provision of the Bill of Rights even arguably requires a government to tolerate serious physical harm on anything like the scale of the devastation worked by handguns," it states.

Although the case decided by the appeals court was called Parker v. District of Columbia, District lawyers have filed their petition as District of Columbia v. Dick Anthony Heller. That is because the appeals court found that Heller, a security guard, was the only one of the six plaintiffs who had legal standing to challenge the law. His application for a handgun permit was denied by the government.