The high court struck down the District of Columbia's ban on handguns, ruling that Americans can keep guns at home for self-defense. It was the justices' first-ever pronouncement on the meaning of gun rights under the Second Amendment.
But the court said the right to bear arms is not absolute and suggested that the ruling should not affect federal restrictions on the sale of guns or who may own them and where they may be carried.
"Gun rights advocates now have a fully recognized individual right to bear arms. But gun control advocates now have a Supreme Court ruling that declares that this right, like other rights in the Constitution, is not absolute. So we finally get some clarity in an area of the law that was begging for it," writes CBS News chief legal analyst Andrew Cohen.
Across the country, mayors in urban centers reacted to the ruling.
"In limiting its opinion to the matter of self-defense, and in saying the right is not absolute, the United States Supreme Court decision today is an explicit statement of support for cities all across America who are creating reasonable measures to limit the ability of those who will do harm, who will maim, who will buy, carry weapons illegally," Philadelphia Mayor Michael Nutter said.
In San Francisco, which has some of the toughest handgun regulations in the U.S., Mayor Gavin Newsom said the ruling "just flies in the face of reality. You just wish the Supreme Court could spend a week in public housing and then come out with this decision. It's very easy and comfortable to stand there with security guards and metal detectors and make these decisions."
San Francisco bars people from carrying handguns on county property, including in parks, schools and community centers. Newsom said city attorneys have been researching new regulations that might place tighter controls on ammunition and further restrict where guns could be carried.
District of Columbia Mayor Adrian Fenty responded with a plan to require residents of the nation's capital to register their handguns. "More handguns in the District of Columbia will only lead to more handgun violence," Fenty said.
After Thursday's decision, gun-rights groups filed a lawsuit against Chicago's handgun ban, which closely resembles the Washington law that was struck down. The National Rifle Association planned to file a similar complaint against San Francisco.
Cohen cautions that the ruling will not "immediately end all gun control regulation around the country. Jurisdictions that want to control guns - especially outside the home - still will be able to do so in some fashion."
Chicago, which passed a gun ban similar to Washington D.C.'s 25 years ago, had 325 gun homicides last year, including a 10-year-old shot in the head, a pregnant woman gunned down and a college student shot and killed, reports CBS News correspondent Bill Whitaker.
Chicago Mayor Richard Daley said the court's ruling was "a very frightening decision" and predicted greater violence if his city's law was overturned.
Laurence Tribe, a constitutional law professor at Harvard Law School, predicted that the ruling could open the door to challenges of regulations already adopted by state and local governments nationwide.
"Now it's going to be open season on gun regulations," he said. "I think we're going to see a cottage industry of lawsuits against gun regulations, even regulations that in the end are going to be upheld."
Robert Levy, an attorney with the libertarian Cato Institute who organized the case against the District of Columbia, said he expected the decision to help create a framework to clarify which laws pass constitutional muster.
"This skeleton is going to have to have some flesh put on it," he said of the decision. "That is going to have to be done through further litigation."
The high court said nothing in its ruling should "cast doubt on long-standing prohibitions on the possession of firearms by felons or the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings."
Some states, like New Jersey and Massachusetts, weren't so concerned about the decision, believing the court had expressed its distaste for D.C.'s flat-out ban but left room for some firearms regulation.
"We regulate the possession of handguns - we don't ban handguns," said New Jersey Attorney General Anne Milgram. "But we have strict licensing requirements, and we are prepared to maintain those requirements and vigorously enforce our laws."
New Jersey requires purchasers of any firearm to obtain a permit before purchase. Federal law only requires purchasers have a background check at the time of purchase.
In New York City, Mayor Michael Bloomberg said "fighting illegal guns has nothing to do with the Second Amendment rights of Americans." He said local authorities "have a responsibility to crack down on illegal guns and punish gun criminals, and it is encouraging that the Supreme Court recognizes the constitutionality of reasonable regulations."
The ruling was celebrated in gun shops, by gun-rights advocates, and elected officials who support greater freedoms for gun owners. The White House embraced the decision even though it went farther than the Bush administration had wanted.
Meanwhile, victims of violence and leaders of jurisdictions with gun laws similar to Washington's said the decision would only encourage violence.
"There are so many guns on the streets," said Pamela Bosely, a Chicago resident whose 18-year-old son Terrell was fatally shot in 2006. "If you didn't have the guns, we'd still have our children."
Washington's handgun ban went into effect in 1976, an attempt to stop a wave of gun-related violence. City residents cannot keep handguns in their homes, with the exception of law enforcement officials and those who owned guns before the ban.
The law's effectiveness is questionable. More than 8,400 people have been killed in the past 32 years, many with handguns.
Fenty, the mayor of the District of Columbia, said Thursday that the city has 21 days to draft new regulations for handgun registration, but that during that time, the ban remains in effect.
In Washington's Trinidad neighborhood, where police recently set up controversial vehicle checkpoints to reduce gun violence, reaction to the court's ruling was mixed.
Sadie Kirkland said the Supreme Court's decision has "legalized the turf and gun war." Kirkland, whose brother was shot and killed in 1995 by a friend in a dispute over guns, feared the city's crime would soar following the ban's dissolution.
But Wilhelmina Lawson, who lives several doors down, disagreed. She said she grew up with guns and believes that as long as people are responsible they should be allowed to own them. "If they ban honest people from having guns, the people doing the killing will still get them," she said.
People offered similar comments near Henderson, Ky., where a worker opened fire at a plastics plant earlier this week, killing five co-workers and himself. The gunman was known to have kept a .45-caliber pistol in his car, which is legal in Kentucky.
"The law is scattered around these parts, and everyone has a right to have a gun," said Jimmy Mooney, who described himself as semi-retired.
Coal miner Kyle Lea, 28, said the slayings reinforced his belief that gun ownership should be closely regulated.
"I just don't believe in guns. I don't like guns, period. And I don't think really anybody should be allowed to have guns."