The District of Columbia's fight to preserve its nearly 32-year-old ban on handguns before the U.S. Supreme Court has drawn nationwide attention as a bellwether vote on the limits of gun control.

"Regardless of who wins and loses, the crucial thing is really going to be what [the justices] are going to say about the Second Amendment," said Paul Helmke, president of the Brady Campaign to Combat Gun Violence. "It will set the ground rules for analyzing almost every gun law in the country for years to come."

Attorneys for the city and Dick Anthony Heller — a special police officer whose failed effort to register a handgun in 2002 helped spur the legal battle —will argue their cases before the justices on Tuesday.

Both sides in the case, along with city officials, federal lawmakers and the White House, say the court's decision places much at stake.

"It'll be an issue as important as abortion, gay marriage — these flash points that so divide us in the United States," said interim D.C. Attorney General Peter J. Nickles, who has led the city's efforts to keep its gun ban.

Widespread impact

The case will mark the first time in about 70 years that the Supreme Court has examined the Second Amendment, which states: "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 rarity of the case and the potential consequences of the ruling account for the widespread attention it has received: Nearly 70 amicus briefs have been filed on behalf of more than 320 members of Congress, 36 states and other interested parties on both sides of the case.

The most notable U.S. city to submit a brief is Chicago, which, aside from the District, potentially has the most to lose or gain from a court decision.

In 1982, Chicago enacted a ban similar to the District's, forbidding handgun registration, with some exceptions.

"The Heller case is obviously of a greater interest to people locally, both within city government and to residents as well, as I think it is to people across the country," said Benna Ruth Solomon, Chicago's deputy corporation counsel, who steered the drafting of the city's brief to protect its ban.

Ms. Solomon said there are "several steps" before a decision in the District's case would affect Chicago's ban or the gun laws of other cities and states.

For example, the court would have to rule that the Second Amendment is "incorporated" by the 14th Amendment against the states — meaning the amendment applies to state and local governments and not just to federal lawmakers.

Such a ruling would go beyond the question the court intends to address, but the justices have authority to exceed those boundaries.

"Our brief was really extremely prophylactic in nature," Ms. Solomon said. "It is not because we are directly affected by the case. It is more because we don't wish to be directly affected by the case."

Alan Gura, an attorney for Mr. Heller who will argue before the Supreme Court, said a ruling in his favor could put gun prohibition "off the table."

"Basically, gun laws that make sense, gun laws that are designed to help police solve crime ... are not going to be affected," said Mr. Gura, who will argue against the District's lead counsel in the case, former acting U.S. Solicitor General Walter E. Dellinger III.

Others who have weighed in on the case include county prosecutors worried that the court's decision could result in appeals from convicted criminals.

A brief filed by district attorneys from San Francisco, New York and elsewhere states that "Second Amendment challenges to criminal laws already have begun."

"A felon convicted of criminal firearm possession recently challenged a New York gun possession statute based on the D.C. Circuit's opinion ... saying he wanted to see 'how far [he] could ride this pony,' " the brief states.

Anthony Girese, counsel to Robert T. Johnson — the district attorney for Bronx County in New York — said if the Supreme Court rules that gun ownership is an individual right and that the Second Amendment applies to the states, the justices then could decide the proper standards for gun regulation.

That, he said, "could have a very profound effect nationwide."

"A lot of major cities, including New York, have fairly restrictive gun regulations," Mr. Girese said. "I would anticipate that if we get to [that level] there will be a vast volume of litigation about the validity of all sorts of criminal laws."

The court's pending decision — which is expected to come down in June — also has caused the Bush administration to question the effect the ruling may have on existing federal laws, including those that generally ban machine guns and weapons undetectable by metal detectors.

U.S. Solicitor General Paul D. Clement, who also will weigh in before the high court on Tuesday, filed a brief in the case urging the justices to send the Heller case back to the lower court for more consideration. He said the appellate panel used a wrong and dangerous approach when it concluded that the District cannot ban handguns because they are "Arms" referred to in the Second Amendment.

"Such a categorical approach would cast doubt on the constitutionality of the current federal machine gun ban, as well as on Congress's general authority to protect the public safety by identifying and proscribing particularly dangerous weapons," the brief states.

The solicitor general's brief also affirms the administration's view that the Constitution guarantees an individual right to gun ownership.

'More than just a gun case'

The District's gun ban, the most stringent in the nation, was passed in June 1976 in a 12-1 vote by the D.C. Council.

It prohibits city residents — with few exceptions — from registering handguns and keeping them in the city. It also requires legal firearms such as shotguns and rifles to be stored disassembled or bound with trigger locks.

In February 2003, Mr. Heller and five other residents sued the city in U.S. District Court, hoping to win the right to keep handguns and an assembled shotgun in their homes for self-defense.

"I was upset in 1976, but I didn't know anything about politics," Mr. Heller told The Washington Times last week. "So I just said 'Oh, obviously some intelligent citizen is going to take care of this for us.' Here we are; I'm the last one standing."

Judge Emmet G. Sullivan, appointed to his post by President Clinton in 1994, dismissed the case about a year later. However, a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit reversed the decision last March, ruling 2-1 that the right to bear arms as guaranteed in the Second Amendment applies to individuals and not only to militias.

Mr. Heller, 66, who lives in Southeast near the Supreme Court building and will be in attendance for the arguments, is the last remaining original plaintiff. The other plaintiffs were dismissed for lack of standing.

He said the case "hasn't changed me at all."

"It's simply an event that's bigger than this citizen, and it represents so much more than just a gun case. It represents defending our Constitution," he said.

D.C. officials, including Mr. Nickles and Mayor Adrian M. Fenty, a Democrat, weighed their decision to appeal the case to the Supreme Court amid warnings from gun-control advocates that the breadth of the District's ban could endanger existing gun laws across the country.

"The fact that it's dealing with the District's gun ban probably makes it a more difficult case than we would have perhaps liked to have seen argued," Mr. Helmke said. "In effect, they picked the easiest one to attack."

David Vladeck, a professor at Georgetown University's law school, said the ramifications of the court's decision depend on how broadly the nine justices address the case's central question: whether the city's laws violate the Second Amendment rights of individuals who are not affiliated with any state-regulated militia but wish to keep handguns and other firearms for private use in their homes.

"One of the reasons why states and cities are worried about this case is they don't want the court to impose unreasonable rules regarding the restriction of weapons," Mr. Vladeck said.

Mr. Nickles and Mr. Fenty say the city's gun-control laws reflect the will of D.C. residents.

"We listened to those folks," Mr. Nickles said, but "you know, my first job is to win. And I think we can and will."

Federal interests

The effectiveness of gun laws in the District, where warring gangs and a crack cocaine surge helped the city earn its "murder capital" nickname in the early 1990s, has been disputed for years.

FBI statistics show that the District's homicide rate was 32.8 per 100,000 residents in 1975, the last full year before the gun ban was passed by the council.

In 2006, the last full year for which statistics were available, the rate of homicides and non-negligent manslaughters in the city was 29.1. The rate dropped immediately after the ban was imposed and skyrocketed in the late 1980s and early 1990s. It has leveled off in recent years. The murder rate peaked in 1991, when the city of just less than 600,000 reported 482 homicides — a murder rate of 80.6 per 100,000 residents.

The handgun ban also has been a subject of congressional debate and even has split the Bush White House.

In 2004 and 2005, congressional efforts to render parts of the city's gun laws obsolete failed despite receiving an overwhelming support from the House.

Last month, 55 senators and 250 members of the House signed onto a brief calling for the Supreme Court to overturn the D.C. gun ban by affirming the circuit court decision. The number of federal lawmakers, including 228 Republicans and 77 Democrats, is thought to be the largest ever to weigh in on a topic with the high court, at least in recent years.

"If you look at the briefs that have been filed on this case, the congressional brief is truly historic," said Wayne LaPierre, executive vice president of the National Rifle Association, which opposes the gun ban. "What you see there is the people's branch of government weighing in that it's the people's freedom, and they want it protected."

Vice President Dick Cheney, breaking with Mr. Clement's brief on behalf of the administration, signed on with the congressional brief in his capacity as president of the Senate.

Eighteen members of the House took a different stance by filing a brief noting that Congress has enacted recent legislation banning certain types of weapons.

"The interesting legal argument we raise is, 'Yes, the Supreme Court interprets the Constitution, but also the Congress interprets the Constitution every day with its legislative actions," said Rep. Chaka Fattah, Pennsylvania Democrat and lead member on the brief. "So if it was constitutional to ban assault weapons or ban weapons in national parks, then there are limits on the right to bear arms."

Mr. Fattah said it is unlikely the court's decision would result in a flurry of federal legislation because of the difficulty of passing gun-control bills in Congress. However, it may become a hot-button topic in the upcoming presidential election.

Sen. John McCain of Arizona, the presumptive Republican presidential nominee, signed on to the congressional brief and co-sponsored previous efforts to lift the ban.

McCain spokesman Randy Scheunemann said the senator thinks the D.C. gun ban is "clearly unconstitutional" and that the Second Amendment guarantees an individual's right to bear arms.

Jen Psaki, a spokeswoman for Democratic presidential hopeful Sen. Barack Obama of Illinois, said Mr. Obama "believes the Second Amendment creates an individual right, and he greatly respects the constitutional rights of Americans to bear arms."

"He also believes that the Constitution permits state and local governments to adopt reasonable and common-sense gun safety measures," she said, but would not elaborate on the whether the senator supports the D.C. gun ban.

The campaign of Mr. Obama's Democratic rival, Sen. Hillary Rodham Clinton of New York, did not respond to repeated requests for comment on the Heller case.

Mr. Nickles said the candidates likely will have to state their views if the court issues a decision. Whether the justices issue a ruling specific to the Second Amendment, the entire country will be watching.

"It's an important, watershed case," Mr. LaPierre said. "There's absolutely no doubt about that."