It was the political punch that everyone saw coming: Virginia Republican gubernatorial candidate Jerry W. Kilgore's emotional television ads that denounce Democratic opponent Timothy M. Kaine's opposition to the death penalty.

Virginia's voters overwhelmingly support capital punishment, and any candidate who finds his opponent on the other side of such a popular issue is going to use it. From the start of the campaign, former attorney general Kilgore has highlighted the difference.

But in the closing weeks of the contest, the ads serve a second purpose as well -- to portray Kaine, the lieutenant governor, as a man with different priorities from his political mentor, Gov. Mark R. Warner (D).

Such a distinction could be key on Nov. 8, when Virginians decide on a replacement for Warner, who is riding high in public opinion polls after leading the state for almost four years.

Kaine has based his campaign on the promise that he is the logical choice to "keep Virginia moving forward" since Warner is barred from seeking reelection. But the Kilgore campaign believes it can break open what both sides describe as an extremely close race by portraying the lieutenant governor as a chameleon who doesn't share Warner's middle-of-the-road persona.

The strategy is "separating Kaine from Warner and further making the case he's not Mark Warner part two," said a Republican strategist familiar with the campaign who would discuss campaign tactics only on condition of anonymity. "It is probably one of the most crucial elements for success."

Although Warner makes a point of not criticizing Kilgore directly -- or even mentioning him by name if he can help it -- he has been lavish in his praise of Kaine, holding fundraisers on his behalf, campaigning with him around the state and appearing in television ads in which he praises Kaine's "guts."

But Kaine needs more than Warner's endorsement in a state that leans Republican. "Mark Warner had the ability to appeal to different constituencies because he ran to the center on social issues, it was hard for Republicans to characterize Warner as too liberal," said George Mason University political science professor Mark J. Rozell, who is closely watching the race.

"Tim Kaine doesn't quite have all of that protection."

Kilgore, who has tried to expand the kinds of crimes that would be eligible for the death penalty, has talked about Kaine's opposition throughout the campaign. But even Democrats were unprepared for the stark and emotional tone of his ads.

One features the widow of a Winchester police officer whose husband was killed in the line of duty. "How could you not think the death penalty was appropriate" for her husband's killer, asked Kelly Timbrook. "When Tim Kaine calls the death penalty murder, I find it offensive."

The other ad shows Stanley Rosenbluth, whose son and daughter-in-law were murdered in 1993. Kaine was involved in representing the killer, who was later executed. "No matter how heinous the crime, he doesn't believe that death is a punishment," Rosenbluth says. "Being as liberal as he is on the death penalty, he's not representing everybody in the state."

Kaine immediately responded with his own ad, which has him directly addressing the camera. "My faith teaches that life is sacred," said Kaine, who speaks often on the campaign trail about his strong Catholic beliefs. "That's why I personally oppose the death penalty. But I take my oath of office seriously, and I'll enforce the death penalty . . . because it's the law."

Several Democratic activists were taken aback by Kilgore's strong ads, and although they would not criticize the Kaine campaign openly, they said they were disappointed with Kaine's measured response. Kaine press secretary Delacey Skinner disagreed.

"Having Tim state his position very clearly is what people want to know," she said, adding that it has proven effective when Kilgore has raised the issue previously. In a Washington Post poll last month, respondents were given Kaine's position -- that he is personally opposed to the death penalty but says he will enforce it because it is state law -- and 63 percent said they thought he would keep his word. Thirty percent said they thought he would not.

The death penalty is always a potent issue in the South, and Virginia ranks third among states in executions in modern times. Still, the rate has slowed considerably. Warner, has never used his position to grant clemency, and Virginia has carried out 11 executions during his term. His Republican predecessors, James S. Gilmore III and George Allen, oversaw 37 and 24 executions, respectively, in their four-year terms.

Some leading Democrats were less worried about the popularity of the death penalty, though, than about Kilgore's campaign to make Kaine seem out of step with Warner and mainstream Virginia voters.

University of Virginia professor Larry J. Sabato, who served as moderator for a debate between Kilgore and Kaine on Sunday night, said that the ads were "powerful" and that Democrats were right to be concerned about the bigger picture.

"What this does is introduce the doubt that will enable Republicans and maybe just conservative independents to say, 'Maybe we don't know the whole story' " about Kaine, Sabato said. "It's going to be tough for Warner to defend Tim Kaine except to say what Kaine is already saying," that he will enforce the law.

But Kaine strategists say Republicans will not be able to exploit differences between the two Democrats.

"It's hard to make the case that Tim Kaine is not the logical successor when Mark Warner is on the air saying that he is the logical successor," said Kaine communications director Mo Elleithee.

Staff writers Chris L. Jenkins and Michael D. Shear contributed to this report.

Lt. Gov. Timothy M. Kaine, right, a Democrat, personally opposes the death penalty because of his religious beliefs, although he has said he would uphold Virginia's law. Republicans are trying to draw distinctions between him and Gov. Mark R. Warner, left, a popular Democrat.Republican Jerry W. Kilgore has worked throughout the campaign to make the death penalty an issue.