An exultant Gov. James S. Gilmore III hailed the legislature's historic Republican majority yesterday as a "new moment" for Virginia and pledged to work with minority Democrats and his own "unruly" GOP allies in the next General Assembly.

Basking in the results of elections Tuesday that left his party in control of both chambers of the General Assembly for the first time, Gilmore used a Capitol news conference to claim a mandate from voters.

"Let me be clear that I believe that this election is a mandate by the people of Virginia for the Republican Party," the governor said. He pledged to shoulder "our burden . . . our duty" to meet what he sees as the voters' conservative-leaning expectations.

On Tuesday, voters put Republicans in 52 of the 100 seats in the House of Delegates and left intact the GOP's 21-to-19 majority in the Senate. But Gilmore, who maintained throughout the campaign that the election was not a referendum on his administration, won no guarantees that the new majority in the legislature will hand him all he wants.

"It isn't my majority," he said.

Some GOP veterans of the rough-and-tumble legislative sessions said much the same thing.

"I don't think you're a rubber stamp for the governor," said Del. John H. "Jack" Rust Jr., of Fairfax County. "We'll work with the governor, but as a team, not as a silent partner."

Competing regional interests among legislators could undermine efforts at a united front among Republicans, lawmakers said.

"The agenda for Northern Virginia is going to be pushed regardless of the partisanship of it," said Del. Harry J. Parrish (R-Manassas). "The Democrats and the Republicans in Northern Virginia are concerned with the same issues . . . education and transportation."

Gilmore also acknowledged the potential for a long battle with Democrats in the final two years of his term as he and legislative Republicans redraw the lines of every political district in the state after the 2000 Census. The party in power after the census draws the boundaries to favor the election of its candidates for state and federal offices.

"We're all looking forward to see how this plays out" with the legislature, Gilmore said somberly. U.S. Rep. Thomas M. Davis III (Va.), chairman of the National Republican Congressional Committee, predicted in Washington yesterday that Virginia Republicans could pick up two or three seats in Congress in 2002 with the help of redistricting.

Democrats, who feasted on the spoils of power during the 20th century, predicted that the new Republican majority could be unwieldy for Gilmore. Christian conservatives will demand more, the Democrats said, as will Northern Virginia Republicans seeking investment in transportation and education.

"One or two free spirits can create untold misery for the so-called majority government," U.S. Sen. Charles S. Robb (D-Va.), a former governor, said on election night.

Members of both parties speculated widely on the future of state Sen. Warren E. Barry (Fairfax), who angered other Republicans when he gave $75,000 of his campaign funds to his son Stanley G. Barry, a Democrat who ran a successful campaign to become sheriff in Fairfax County.

Warren Barry said he will make a decision next week, after meeting privately with Gilmore, on whether to maintain his three-decade-old affiliation with the GOP. Barry is chairman of the Senate Transportation Committee--a position some Republicans threatened to strip from him.

"If [Gilmore] in fact did that, then I'm gone," Barry said.

Gilmore declined to list specific areas where he and Democrats may find common cause, but he did suggest that transportation could be one avenue for cooperation, "now that we've shown the way for transportation opportunities without having to raise their taxes."

In late August, just as many voters were tuning in to the legislative elections, Gilmore went to traffic-clogged Northern Virginia to unveil a plan to raise nearly $2 billion for new roads, relying on a series of funding sources, some of which were adamantly opposed by Democrats.

Under Gilmore's initiative, the state would provide only a modest fraction of the $11 billion in new money that a bipartisan commission in the Washington suburbs projected the region needs just to stay even with its pressing traffic needs.

Business leaders have been urging Gilmore to consider a tax increase for highways--even some of his Republican supporters favor it--but he has been steadfastly against the idea.

That, say GOP leaders and Democrats alike, could fuel the simmering arguments about Virginia's haves and have-nots, regional disputes that Gilmore accepted yesterday as a fact of political life.

"There will be regional divisions," he said. "That's certainly healthier than a straight-up partisan division."

Legislative veterans disagreed. "He's got a legislature that's going to be divided not on partisan lines but on regional lines," said Del. Kenneth R. Plum (Fairfax), the state Democratic chairman, who won reelection to the House on Tuesday after 20 years in the assembly.

"They're splintered much farther and more radically than we are," he said. "And we'll take advantage of that."

Del. Linda T. "Toddy" Puller (D-Fairfax), who won a promotion to the state Senate in Tuesday's voting, said: "We'll still go forward with our safe schools proposal, and I'm sure we will still go forward with our transportation proposal. I think our side would still like to do away with the food tax."

Gilmore said democracy is served no matter how heated the conversation gets between governor and legislature, or among lawmakers themselves.

"There's nothing wrong with debating any issue, left, right, center, over, under, around or through," Gilmore said.

Minutes later, he added: "I don't expect there to be a Republican majority forever and ever."

Gilmore laid out only a handful of governing goals, sidestepping the issue of school vouchers by saying he would like to see better use made of a charter school law already on Virginia's books.

He also made it clear he would leave to "the next governor" any serious rewrite of the state's tax code, which penalizes local governments, especially older cities, for their reliance on income from property taxes.

However, other officials said the administration is already exploring selling off some of Virginia's antiquated mental health institutions, notably Eastern State Hospital in Williamsburg, saying home-based care and outpatient medicine may be more cost-efficient alternatives.

Gilmore also plans to redouble his long-standing effort to hire 4,000 new teachers and will press more energetically for his New Century Scholarship program to encourage academic excellence, an adviser said. The scholarship idea has languished for two years.

The governor said he would stay out of the looming fight among Republican lawmakers over who will be the new speaker of the House of Delegates, but the front-runner, Del. S. Vance Wilkins Jr., a 22-year stalwart from the Lynchburg area, told reporters he had the votes.

Republicans will meet in Richmond in their legislative caucus groups Nov. 14 to pick their choice for speaker. Wilkins said his political action committee had spread more than $250,000 around Virginia to help candidates and finally win a GOP-led House.

Rust was working the phones yesterday in his campaign to become the first Republican speaker in a century, but even if he does not win that powerful position, he and other GOP colleagues will enjoy broad authority in the assembly, making policy on a wide variety of issues, including education and transportation, as well as the annual state budget and revenue-raisers such as taxes.

"What you're seeing is a watershed," Rust said. "The suburban senators and delegates are moving into ascendancy in the General Assembly."

Melton reported from Richmond and Timberg from Washington. Staff writers William Branigin and Alan Sipress contributed to this report.

CAPTION: At news conference, Gov. James S. Gilmore III said the new GOP legislative majority "isn't my majority." At left is Attorney General Mark L. Earley.