WASHINGTON — The Supreme Court on Thursday ruled for the first time that the 2nd Amendment explicitly protects Americans' right to own guns for self-defense -- resolving one of the Constitution's oldest disputes and reviving the debate over gun rights, crime and violence.
The landmark decision struck down a District of Columbia ordinance, the strictest in the nation, that barred homeowners from keeping handguns. The ruling brought immediate court challenges to similar laws in Chicago and San Francisco.
In a 5-4 decision, the court said that "the right of the people to keep and bear arms" is not limited to state militias, as some historians have argued. Rather, it protects "the inherent right of self-defense," Justice Antonin Scalia said. Joining him in the majority were Chief Justice John G. Roberts Jr. and Justices Samuel A. Alito Jr., Anthony M. Kennedy and Clarence Thomas.
The four dissenters -- Justices John Paul Stevens, Stephen G. Breyer, Ruth Bader Ginsburg and David H. Souter -- said the majority had unwisely opened the door to legal attacks on popular and effective gun-control measures. "I fear that the District's policy choice may well be just the first of an unknown number of dominoes to be knocked off the table," Stevens wrote in his dissenting opinion.
Scalia stressed that the decision, though historic, was narrow and its practical effects limited.
"Nothing in our opinion should be taken to cast doubt on long-standing prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places, such as schools and government buildings," he wrote. The majority opinion also said that prohibitions on carrying concealed or dangerous and unusual weapons, such as machine guns, were not in doubt.
Scalia did not say how 2nd Amendment rights were to be evaluated. "Since this case represents this court's first in-depth examination of the Second Amendment, one should not expect it to clarify the entire field," he wrote.
Gun rights advocates Thursday made it clear that they would pursue more legal challenges, providing ample opportunity for the high court to revisit the issue.
"It looks to be a phenomenal day for gun owners and District of Columbia residents," said Wayne LaPierre, chief executive of the National Rifle Assn. "The next step is to ensure that every American has access to this right."
Gun control advocates, however, took heart in the fact that the ruling left room for some gun regulations.
"While we disagree with the Supreme Court's ruling, which strips the citizens of the District of Columbia of a law they strongly support, the decision clearly suggests that other gun laws are entirely consistent with the Constitution," said Paul Helmke, president of the Brady Campaign to Prevent Gun Violence.
On the presidential campaign trail, Republican John McCain and Democrat Barack Obama were supportive of the court's ruling.
While calling the decision "a landmark victory for 2nd Amendment freedom," McCain said it did not "mark the end of our struggle against those who seek to limit the rights of law-abiding citizens." He also took a jab at a controversial statement Obama made in April, adding: "Unlike the elitist view that believes Americans cling to guns out of bitterness, today's ruling recognizes that gun ownership is a fundamental right -- sacred, just as the right to free speech and assembly."
For his part, Obama drew a somewhat different lesson from the court's decision. He said it endorsed both gun rights and reasonable regulation.
"I have always believed that the Second Amendment protects the rights of individuals to bear arms, but I also identify with the need for crime-ravaged communities to save their children from the violence that plagues our streets through common-sense, effective safety measures," he said.
"I know what works in Chicago may not work in Cheyenne. We can work together to enact common-sense laws, like closing the gun-show loophole and improving our background-check system, so that guns do not fall into the hands of terrorists or criminals."
A White House statement said that President Bush "strongly agrees with the Supreme Court's historic decision today that the 2nd Amendment protects the individual right of Americans to keep and bear arms."
Scalia spent most of his 64-page opinion explaining why history was on his side. He cited the Stuart kings of England and how they had used their militias to disarm their opponents. "By the time of the founding [of this country], the right to have arms had become fundamental for English subjects," he said. "There seems to us no doubt, on the basis of both text and history, that the Second Amendment conferred an individual right to keep and bear arms."
But in his 46-page dissent, Stevens accused Scalia of misreading the words of the 2nd Amendment and spinning its history to ignore its focus on organized militias.