The shooting rampage in Virginia may revive the issue of gun control in the 2008 presidential contest and unravel what had been a growing consensus among Democrats not to mention the subject.

“This is an issue that shows up during tragedies,” a Democratic gun policy analyst and former aide to Senator Schumer, James Kessler, said. “That is the nature of the gun issue. It will recede from view and then, unpredictably, burst upon the scene.”

In recent years, Democratic politicians and campaign advisers have blamed losses at the polls on the perception that their party is anti-gun. President Clinton contended that Vice President Gore’s defeat in the 2000 presidential campaign was attributable in part to a National Rifle Association campaign to paint him as a threat to sportsmen and hunters.

Many Democrats have since counseled candidates to soft-pedal the gun issue or drop it altogether. Now, the worst shooting incident in American history has some rethinking the wisdom of that approach.

“You can have a political party, a group, or a leader say, ‘Our strategy is not to deal with this.’ Well, guess what? You’re dealing with this issue. That’s all there is to it,” Mr. Kessler said. “Not just advocates, but you’ll have average people saying, ‘Let’s do something about this.'”

Mr. Kessler, who works with a group that says it seeks a middle ground on gun issues, Americans for Gun Safety, said past shooting rampages have led rather directly to major legislative efforts. A 1993 attack that killed eight people at a San Francisco law office helped bring about a federal assault weapons ban the following year. The 1999 attack on Columbine High School in Colorado, in which 12 students and a teacher were killed, led to a protracted debate over closing a “loophole” that allowed the purchase of guns at gun shows without a background check. Congress deadlocked over legislation to address the issue, but Colorado voters overwhelmingly passed a referendum in 2000 to close the so-called loophole in that state.

Presidential candidates gave no indication yesterday of whether they plan to retool their campaigns to devote more attention to gun control. Observing a sense of decorum, most candidates released written statements expressing condolences over the deaths but saying nothing about how they could have been prevented.

Senator Clinton said she was “shocked and saddened by the horrific tragedy.” Senator Obama of Illinois also expressed shock, adding, “Violence has once again taken too many young people from this world.”

Mayor Giuliani announced that he was canceling his campaign events for today, including a speech at Regent University in Virginia Beach, Va. “On this day of national tragedy, when we lost some of our finest to a senseless act, we stand together to mourn those who lost their lives,” he said.

The NRA deplored the tragedy but declined to comment on the potential fallout from the shooting “until all the facts are known,” a spokesman for the group, Andrew Arulanandam, said.

If the incident stokes the public’s appetite for additional gun laws, it could work to the advantage of candidates whose pro-gun control views were previously seen in some circles as a liability. Similarly, those hoping to profit from staunch opposition to gun controls could be hurt. Among Republicans, Mr. Giuliani, who was a strong gun control advocate as mayor, would be the most obvious beneficiary. Among Democrats, Governor Richardson of New Mexico, who was attempting to claim the pro-gun vote in his party, could lose some steam. The emergence of the issue could also bolster Mayor Bloomberg, who is believed to be mulling an independent bid for the presidency, despite his denials of interest.

One prominent opponent of gun control conceded that the shootings were certain to spark a drive for stronger gun laws. “There’ll surely be more support than there would have been otherwise for these types of rules,” the author of “More Guns, Less Crime,” John Lott Jr., said. However, he said the issue might recede a bit if President Bush doesn’t pursue it. “Obviously, if Clinton was president right now, it would get a lot more oxygen.”

Mr. Lott said the shootings demonstrate the foolishness of laws and regulations forbidding guns at schools. “Who’s going to obey that?” he asked. “They unintentionally create a safe zone for the killer and make it so they have more time to go and do more carnage.”

He noted that most mass shootings, including the one yesterday, end with the gunman being shot or killing himself. “Normal law enforcement stuff we use, that works so well for other crimes, doesn’t even work,” he said. “You’re going to expel the guy who killed 30 people?”