Washington ? With Thursday’s decision, the Supreme Court pushed the gun issue to the forefront of the nation’s agenda, opening a new chapter in what has been one of the most contentious and divisive debates in American politics for the past four decades.

Advocacy groups braced for new skirmishes, both in the courts and in the legislatures. Gun rights advocates, hailing what they called an historic milestone, immediately targeted other jurisdictions with laws similar to those in Washington D.C., whose gun ban was struck down Thursday. Defenders of gun control took heart from language in the ruling acknowledging the constitutionality of some reasonable restrictions while warning of a new assault on those restrictions.

Barack Obama and John McCain both endorsed the essential finding in the court’s decision in District of Columbia v. Heller. But the gap between their past positions on gun control sparked a resurgence of a cultural debate between the two presumptive nominees that likely will continue until November.

Historical significance

The historical significance of Thursday’s ruling was more obvious than what the practical impact may be, given that it was the first time the high court declared that the Second Amendment guarantees an individual right to gun ownership.

“This (debate) has been huge for a long time and the court has ducked it,” said Nicholas Johnson, a professor of law at Fordham University. “So historically it’s important because the gun issue divides us so substantially and because we’ve finally gotten some resolution, but also because we’ve gone so long without a resolution.”

Historian Alan Brinkley of Columbia University said that while the court struck a balance between rights and restrictions, “the movement has been toward greater and greater regulation of guns and this is a step back – maybe not a big step back but certainly a symbolic one. It raises the question of how many more steps back the court might take.”

Mixed reactions

Sen. Dianne Feinstein, D-Calif., who became mayor of San Francisco in 1978 after the then-mayor George Moscone was shot and killed in city hall, said the decision is going “to open the doors to litigation against every gun safety law that states have passed – assault weapons bans, trigger locks, and all the rest of it.”

Mayor Richard M. Daley of Chicago, whose strict gun control law now faces challenge, said the ruling was “a very frightening decision,”and asked, “Does this lead to everyone having a gun in our society?”

Mayor Michael Bloomberg of New York, who has put together Mayors Against Illegal Guns, a coalition of 320 mayors, reacted more cautiously, noting that efforts to fight illegal guns “has nothing to do” with Second Amendment rights.

“Today’s decision by the Supreme Court upholding those rights will benefit our coalition by finally putting to rest the ideological debates that have for too long obscured an obvious fact: criminals, who have no right to purchase or possess guns, nevertheless have easy access to them.”

But Chris Cox, chief lobbyist for the National Rifle Association, called the ruling a “monumental decision” that will prompt more challenges and more debates. “This has put politicians on notice that this is a fundamental right. It can’t be rationed. It can’t be unduly restricted on the whims of local officials.”

A part of our culture

Guns are embedded in American culture as in no other developed nation in the world. From the Revolution to the frontier of the Wild West to the traditions of rural and small-town life, guns have occupied a central role in American history and national mythology. David Kennedy, the Stanford University historian, described the attachment as a reflection of the deep strain of individualism that is part of the nation’s cultural identity, linked to suspicion of authority and power and strong central governments. It has manifested itself in a powerful movement to protect Second Amendment rights.

With urbanization came a backlash against the unfettered availability of guns, and the modern gun control movement gained force after the assassinations of Robert F. Kennedy and Martin Luther King Jr. in the 1960s. With each horrifying incident of gun violence, now captured in names like Columbine and Virginia Tech, advocates of gun control have called for further restrictions.

But the passion has been largely on the right, led by organizations like the NRA. Democrats have lamented their inability to win more votes in rural America and particularly in parts of the West and South, and have tried to calibrate their positions on guns to make themselves more acceptable to voters in those regions.

Obama, who has been an advocate of strict gun control laws and who spoke favorably about the Washington D.C.’s gun ban before Thursday’s ruling, said in a statement, “I have always believed that the Second Amendment protects the right 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. The Supreme Court has now endorsed that view.”

McCain applauded the decision and chastised Obama for failing to sign a bipartisan amicus brief calling for the court to act to strike down the city’s ban on handguns. “This ruling does not mark the end of our struggle against those who seek to limit the rights of law-abiding citizens,” he said. “We must always remain vigilant in defense of our freedoms.”

Gun politics

Some Democratic strategists saw Thursday’s ruling as one that would deprive conservatives of one of their most extreme arguments – that Democrats are trying to take away all guns. “Whatever you believe about the merits of the decision, it’s a decision that protects Democrats from the charge that they want to ban all guns because the Supreme Court has said you can’t do that,” said Democratic pollster Geoffrey Garin.

Mark Mellman, another Democratic pollster, predicted that the decision will energize those on the left, who favor some restrictions and who may see the ruling as a step toward wiping more of those away. “The decision might actually allow the supporters of gun control to get back into the conversation in a way they haven’t been for quite some time.”

“We’ve cleared the way to talk about the real issues,” said John Feinblatt, the criminal justice coordinator for Bloomberg. “It concludes the debate and lets us focus on what’s clearly important.”

Two Republican strategists saw political advantages for conservatives from the ruling. “What it really creates is uncertainty,” Alex Castellanos said. “I think a lot of people who are concerned about the Second Amendment, like the NRA, will look at the 5-4 decision and say we barely hung onto the right to bear arms. This is going to motivate Republicans to vote.”

Neil Newhouse, a GOP pollster, agreed that the ruling could help McCain in western battleground states such as Colorado, New Mexico and Nevada, where there is strong support for Second Amendment rights. But Democrats said McCain could face new problems among suburban women in other battlegrounds.

Several analysts noted that the court decision had found a balance about where public opinion rests: in support of the right to own guns but also supporting some restrictions. “The ruling has taken away the two extremes of the debate, said Paul Helmke, president of the Brady Campaign to Prevent Gun Violence. He added: “This has been a wedge issue for years and I think they’ve taken away the wedge.”

That could usher in less contentious debate over the gun issue. But the recent history of gun politics suggests that it may take time for that occur.