Democrat Timothy M. Kaine eked out a narrow victory in the race for lieutenant governor of Virginia yesterday, riding a promise to transcend partisan divisions while capitalizing on the party's strong showing at the top of the ticket to defeat Republican Jay K. Katzen.

Kaine's 50 percent to 48 percent victory was the closest of the three statewide races. The win was made possible by lopsided Democratic victories in a handful of places, including Arlington County and Alexandria in Northern Virginia, industrialized Tidewater areas such as Norfolk and Portsmouth, and Kaine's home base of Richmond, where he served two terms as mayor before embarking on his bid for statewide office.

The victory makes Kaine the party's most likely candidate for governor in 2005. With Virginia governors limited to a single four-year term, the clock was already ticking on Gov.-elect Mark R. Warner last night.

"Tonight, we are one Virginia," Kaine told cheering supporters at Richmond's Marriott Hotel. "The voters voted to end partisan division and negative campaigning."

The curiosity of Kaine's campaign was that his views on prominent social issues were thought to put him too much at odds with many of Virginia's conservative voters. He opposes the death penalty, for instance, and supports abortion rights and some gun restrictions.

But Kaine, 43, a Harvard-educated civil rights lawyer, emphasized throughout his campaign the importance of "reaching across the artificial lines that divide us" and instead focusing on devising solutions.

For example, Kaine liked to highlight a model gun program developed during his time on the Richmond City Council that not only won broad political support but also helped drop the city's homicide rate by 55 percent.

One of his stock lines was: "Now more than ever, it's time we set political divisions aside to work together to improve the quality of life for Virginia's families."

Said Scott Keeter, a pollster and government professor at George Mason University: "Politics in Virginia had a pretty nasty tone for a number of years, and I think the voters were very receptive to his message of bridge-building and getting things done. My sense has always been that Virginia is not as conservative as its reputation."

The Katzen campaign, led by a seemingly indefatigable candidate who put 6,000 miles a month on his Mercury Sable, started out well behind in the polls but had closed the margin as the election neared.

Just after 11:50 p.m., Katzen emerged from his 18th-floor suite at the Omni Hotel to deliver a concession speech to a dwindling crowd. Most of the media had left, the band had packed up and only about 60 supporters remained from the hundreds who had filled the ballroom earlier in the evening.

"I can't pretend that this doesn't hurt, but I leave you with my head held high, my principles intact, my positions unchanged and my pride undiminished over being a conservative, a Virginian and an American," Katzen said.

Katzen, 65, a social conservative and former Princeton cheerleader, began the contest this summer 11 points behind, according to polls conducted by Mason-Dixon Polling and Research Inc., and he was the least known of the statewide candidates. But 35 percent of voters were undecided then. By October, another Mason-Dixon poll showed that Kaine's lead had become so small as to be statistically insignificant.

A member of the House of Delegates since 1994 and a former Foreign Service officer behind the Iron Curtain, Katzen spoke of knowing "the shadowy world from which our security has been challenged." His campaign emphasized experience.

Together, Kaine and Katzen provided voters with a far starker contrast than did the mainline gubernatorial candidates. They disagreed on schools, taxes, abortion, the death penalty, gun rights and a sales tax referendum to pay for roads in Northern Virginia.

The Katzen campaign, however, was set back by two events.

First, an effort by Katzen backers to portray Kaine as an extreme liberal, a supporter of gay marriage and an enemy of such U.S. institutions as the Boy Scouts backfired when newspaper editorials across the state denounced those claims as unsupported. Katzen backed off and was attacked as malicious.

Then the GOP gubernatorial candidate, Mark L. Earley, fared poorly against Warner.

"When you are running for lieutenant governor, it really helps to have a winning candidate at the top of your ticket," said former Democratic lieutenant governor Donald S. Beyer Jr. "A win by Mark Warner is a very good thing for Tim Kaine."

Libertarian candidate Gary A. Reams, 45, who campaigned on the argument that marijuana-prohibition laws have "gone too far," finished a distant third.

Staff writers Steven Ginsberg and David Cho contributed to this report.

"Tonight, we are one Virginia," Timothy M. Kaine told cheering supporters at Richmond's Marriott Hotel. "The voters voted to end partisan division and negative campaigning." Kaine defeated Del. Jay K. Katzen by 2 percentage points.