Every spring, Chicago Mayor Richard M. Daley stands before a table full of confiscated firearms and urges federal and state lawmakers to pass new gun-control measures that he says will keep streets safer. This year, there's a twist: Mayor Daley is at risk of losing a gun-control law he already has.

By the end of June, the US Supreme Court is slated to decide whether the city's 28-year ban on handguns – the last of its kind in the nation – is unconstitutional. If the decision goes against Chicago (and that's where the smart money is), the city will be forced back to the drawing board to find a new balance between gun rights and public safety.

More broadly, say legal experts, such a ruling will spur a slew of challenges to other gun regulations elsewhere – from hurdles to getting gun permits to bans on loaded weapons in public to rules forcing gun owners to keep weapons locked at home.

IN PICTURES: States with the strictest gun laws

The Chicago case is pivotal to Second Amendment defenders. If it goes their way, it will launch "a wide-open, exciting new field of constitutional litigation," says Alan Gura, a lawyer representing the Illinois challengers to Chicago's law. "Once this case is decided and hopefully ... we will prevail ... [Chicago] should look over its laws in good faith and try to see if there are any other problematic [gun] laws that need to be revisited. If the city will not revisit them ... I'm sure the courts will."

If, after 28 years, Chicago residents will again be able to own handguns and to buy them in the city, what effect will that have on public safety?

The answer depends on who's talking.

City police recovered 8,259 illegal firearms in 2009 – a 12.7 percent bump from 2008, according to police department data. The police credit the seizures for 2009's drop in gun-related homicides, down 9 percent from the year before.

But the data are not that clear-cut. There were fewer homicides in 2007 than in 2009, and the homicide count so far this year is on pace to surpass last year's level.

If the Chicago ban is invalidated, "I honestly think we're going to see business as usual," says John Worrall, a criminologist at the University of Texas at Dallas.

Handgun bans, he says, don't work because demand for guns is so high that plenty of people are willing to risk supplying them. Some people go to nearby communities, where there are no bans, to buy handguns. A more effective way to reduce crime, he says, is to weed out gun license applicants on the basis of criminal records and to restrict where people can use or carry handguns.

"Handgun bans target everybody, and that is the core issue," he says. "A broad brush is being applied and is making criminals out of law-abiding citizens."

Chicago police officials refused requests to comment on how fighting crime might change if the ban is lifted. A Chicago street cop, though, notes that when handguns are illegal, it's easy to spot the bad guys. They're the ones with the guns.

"Usually when there's a gun, there's something else," says the 15-year veteran, who asked to remain anonymous because he is not authorized to speak publicly. "I'm all for the right to bear arms, but handguns have one purpose: shooting people. As soon as they make them legal again, we're going to see a lot more incidents."

If the high court puts an end to Chicago's handgun ban, it's likely that the city "will have to look to more permissive forms of handgun regulation," says Robert Batey, a professor at Stetson University's College of Law in St. Petersburg, Fla. "There will probably be efforts in 'how far can we go' in restricting handguns," he says.

New York City's handgun rules might offer a clue. There's no outright ban, but the city and the police operate a permit system. To own or carry a handgun there, applicants must show during a rigorous screening process that they face an extraordinary threat in daily life, such as those that can confront celebrities or Wall Street financiers.

Lawrence Rosenthal, a professor at the Chapman University School of Law in Orange, Calif., who filed a court brief in the Chicago case for the US Conference of Mayors, calls New York's approach "innovative" in showing the courts a sensible approach to legalizing handguns.

"In the big cities, plagued as they are by poverty and violence and criminal street gangs ... we think there are enormous problems there with the liberal availability of firearms," Mr. Rosenthal says. "New York City actually provides a powerful example of what you can accomplish to keep guns off the streets."

But if Chicago were to go the way of New York, that would simply – and unfairly – persecute legitimate gun owners, says Richard Pearson of the Illinois State Rifle Association, which is a plaintiff in the Supreme Court case. He complains about what he sees as onerous rules for rifle owners in Chicago, such as re-registering their firearms every year. "You're at the total mercy of the bureaucracy of the city. And they're not very merciful," says Mr. Pearson.

Chicago officials have been mum about what exactly they will do in the event of a rebuff by the Supreme Court.

"We will carefully review the Supreme Court opinion as well as all of our options at that time," Melissa Stratton, a spokeswoman for Chicago's Department of Law, wrote in a recent e-mail.

Related:

Supreme Court to take up landmark gun-control case

Supreme Court, gun control, and the Second Amendment: a reckoning

Homicide rate jumps in Chicago, Daley pushes for more gun control

IN PICTURES: States with the strictest gun laws