On Sept. 24, 1976, one of the toughest gun laws in the nation took effect in the District of Columbia, essentially outlawing the private ownership of new handguns in a city struggling with violence.

Over the next few weeks, a man with a .32-caliber pistol held up workers at a downtown federal office at midday, a cab driver was shot in the head, and a senator was mugged by three youths, one carrying a revolver, near the U.S. Capitol.

Since the ban was passed, more than 8,400 people have been murdered in the district, many killed by handguns. Nearly 80 percent of the 181 murders in 2007 were committed with guns.

On Tuesday, the Supreme Court is scheduled to hear arguments in a challenge to the city's handgun ban. The case is likely to produce the most important firearms ruling in generations and could undermine other gun control laws nationwide if the court takes an expansive view of the right to bear arms.

The central question is whether the Second Amendment guarantees the right of individuals to bear arms, or instead protects the collective right of states to maintain militias. The court probably won't base its ruling on the effectiveness of Washington's law.

Outside the court, however, a long-debated question is whether a strict gun law like Washington's has any effect on violent crime.

City leaders say the law has kept many guns off the street and warn that violence could increase without it. Firearms still flow in from states like Maryland and Virginia, but District of Columbia officials say the ban reduces the number of legally owned firearms that are stolen or used in domestic killings and suicides.

"Whatever right the Second Amendment guarantees, it does not require the district to stand by while its citizens die," the city wrote in its petition to the Supreme Court last year.

To gun rights advocates, the numbers prove a different point: Violence continues unchecked despite the ban. And while criminals seem to be able to get guns with ease, law-abiding people are being denied the means to protect themselves, they say.

"I should be able to live in the district and protect myself," said Shelly Parker, who said she was harassed and threatened in her former Capitol Hill home by a drug dealer who once tried to break down her door. Parker was a plaintiff in the original case against the city.

Those who live daily with gun violence on Washington's streets, many of them just teens, paint a stark picture of how easy it is to get a firearm. A gun can be bought with a few well-placed calls and a couple hundred dollars.