Silent on central questions of gun control for two centuries, the Supreme Court found its voice Thursday in a decision affirming the right to have guns for self-defense in the home and addressing a constitutional riddle almost as old as the republic over what it means to say the people may keep and bear arms.

The court's historic awakening on the meaning of the Second Amendment brought a curiously mixed response, muted in some unexpected places.

The reaction broke less along party lines than along the divide between cities wracked with gun violence and rural areas where gun ownership is embedded in daily life. Democrats have all but abandoned their long push for stricter gun laws at the national level after deciding it's a losing issue for them. Republicans welcomed what they called a powerful precedent.

Democratic presidential candidate Barack Obama, straddling both sides of the issue, said merely that the court did not find an unfettered right to bear arms and that the ruling "will provide much-needed guidance to local jurisdictions across the country." But another Chicagoan, Democratic Mayor Richard Daley, called the ruling "very frightening" and predicted more violence and higher taxes to pay for extra police if his city's gun restrictions are lost.

Republican presidential candidate John McCain welcomed the ruling as "a landmark victory for Second Amendment freedom."

The court had not conclusively interpreted the Second Amendment since its ratification in 1791. The amendment reads: "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 basic issue for the justices was whether the amendment protects an individual's right to own guns no matter what, or whether that right is somehow tied to service in a state militia, a once-vital, now-archaic grouping of citizens. That's been the heart of the gun control debate for decades.

Writing for the majority, Justice Antonin Scalia said an individual right to bear arms exists and is supported by "the historical narrative" both before and after the Second Amendment was adopted.

President Bush said: "I applaud the Supreme Court's historic decision today confirming what has always been clear in the Constitution: the Second Amendment protects an individual right to keep and bear firearms."

The full implications of the decision, however, are not sorted out. Still to be seen, for example, is the extent to which the right to have a gun for protection in the home may extend outside the home.

Scalia said the Constitution does not permit "the absolute prohibition of handguns held and used for self-defense in the home." The court also struck down D.C. requirements that firearms be equipped with trigger locks or kept disassembled, but left intact the licensing of guns. The district allows shotguns and rifles to be kept in homes if they are registered, kept unloaded and taken apart or equipped with trigger locks.

Scalia noted that the handgun is Americans' preferred weapon of self-defense in part because "it can be pointed at a burglar with one hand while the other hand dials the police."

But he said nothing in the 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."

In a concluding paragraph to the 64-page opinion, Scalia said the justices in the majority "are aware of the problem of handgun violence in this country" and believe the Constitution "leaves the District of Columbia a variety of tools for combating that problem, including some measures regulating handguns."

D.C. Mayor Adrian Fenty responded with a plan to require residents to register their handguns. "More handguns in the District of Columbia will only lead to more handgun violence," Fenty said.

In a dissent he summarized from the bench, Justice John Paul Stevens wrote that the majority "would have us believe that over 200 years ago, the Framers made a choice to limit the tools available to elected officials wishing to regulate civilian uses of weapons."

He said such evidence "is nowhere to be found."

Justice Stephen Breyer wrote a separate dissent in which he said, "In my view, there simply is no untouchable constitutional right guaranteed by the Second Amendment to keep loaded handguns in the house in crime-ridden urban areas."

Joining Scalia were Chief Justice John Roberts and Justices Samuel Alito, Anthony Kennedy and Clarence Thomas. The other dissenters were Justices Ruth Bader Ginsburg and David Souter.

Gun rights advocates praised the decision. "I consider this the opening salvo in a step-by-step process of providing relief for law-abiding Americans everywhere that have been deprived of this freedom," said Wayne LaPierre, executive vice president of the National Rifle Association.

The NRA will file lawsuits in San Francisco, Chicago and several Chicago suburbs challenging handgun restrictions there based on Thursday's outcome.

Some Democrats also welcomed the ruling.

"This opinion should usher in a new era in which the constitutionality of government regulations of firearms are reviewed against the backdrop of this important right," said Sen. Patrick Leahy of Vermont.

The capital's gun law was among the nation's strictest.

Dick Anthony Heller, 66, an armed security guard, sued the district after it rejected his application to keep a handgun at his Capitol Hill home a short distance from the Supreme Court.

"I'm thrilled I am now able to defend myself and my household in my home," Heller said shortly after the opinion was announced.

The U.S. Court of Appeals for the District of Columbia ruled in Heller's favor and struck down the district's handgun ban, saying the Constitution guarantees Americans the right to own guns and a total prohibition on handguns is not compatible with that right.

The issue caused a split within the Bush administration. Vice President Dick Cheney supported the appeals court ruling, but others in the administration feared it could lead to the undoing of other gun regulations, including a federal law restricting sales of machine guns. Other laws keep felons from buying guns and provide for an instant background check.

The last Supreme Court ruling on the matter came in 1939 in U.S. v. Miller, which involved a sawed-off shotgun. Constitutional scholars agree it did not squarely answer the question of individual versus collective rights.

The case is District of Columbia v. Heller, 07-290.