Former Virginia governor James S. Gilmore III (R) said yesterday he opposes the transportation tax proposal on Tuesday's ballot and said his Democratic successor, Mark R. Warner, had failed to make a persuasive case for the tax.

"I just think this is not the right approach to governance," Gilmore said in a telephone interview before announcing his opposition to the tax at a Republican gathering in the Shenandoah Valley. "Raising taxes is always the easy way out, and then you don't have to set priorities or find ways to manage."

While he said he has no plans to campaign against the tax, his opposition puts him squarely at odds with Warner, who is campaigning vigorously for the regional tax increases in Northern Virginia and Hampton Roads.

But Gilmore, whose proposal to eliminate the unpopular car tax propelled him to the governorship in 1997, also has broken ranks with prominent elected leaders in his own party who have campaigned for the tax increase. John W. Warner, the state's senior senator, Reps. Thomas M. Davis III and Frank R. Wolf and a majority of state legislators and county supervisors who represent the Washington suburbs have endorsed the measure.

"It's unfortunate that governor Gilmore lacks the courage to join his fellow Republican colleagues John Warner, Tom Davis and Frank Wolf, not to mention a majority of Republicans in the General Assembly in this area," said Mary A. "Mame" Reiley, campaign director of Citizens for Better Transportation.

"What we're asking voters to do is not an easy thing," Reiley said. "This is the best solution we have, and he should be part of it."

George Allen (R), Virginia's junior senator and governor before Gilmore, also has expressed his opposition to a transportation tax. Allen lives in Fairfax County.

"He and his wife, Susan, have decided they're going to vote against it," said Carrie Cantrell, Allen's press secretary. "He just doesn't think they've made a clear case as to why they should raise taxes at this time."

Many Republican Party activists oppose the two regional tax plans, which call for an increase of a half-cent per dollar in the sales tax in Northern Virginia and a one-cent increase in the Hampton Roads area. The money raised would fund road and transit projects in each region.

Both sides in the Northern Virginia campaign predicted the vote will be close. Polls are open Tuesday from 6 a.m. to 7 p.m.

A Northern Virginia poll by Mason-Dixon Polling & Research Inc. two weeks ago found support for the measure at 49 percent, while 43 percent of respondents said they opposed the tax.

Yesterday, Republicans held separate campaign rallies within six miles of each other in Fairfax County.

The county's Republican leadership had a campaign rally at the offices of Interstate Van Lines in Springfield on behalf of GOP candidates. With few contested elections for federal or state office on this year's ballot, the event drew only a few dozen supporters. The candidates did not discuss the tax measure.

"A very difficult issue for the party," Del. David B. Albo (R-Fairfax) said.

Del. Jeannemarie A. Devolites (R-Fairfax) said she would not attend the overlapping rally at nearby Burke Lake Park, where GOP activists gathered by a picnic table to denounce the tax proposal.

"They'd probably stone me, and the feeling would be mutual," said Devolites, who voted in favor of the referendum during the General Assembly session.

"What does the Republican Party stand for?" James T. Parmelee asked the crowd at Burke Lake. "No tax hike!" the activists yelled, thrusting signs with the same words in the air. Parmelee is among the leaders of the anti-tax campaign.

"There's plenty of waste in government," said Tony Esteve of Springfield, a statistician for the Federal Highway Administration. He said Virginia's tax on gasoline should generate enough revenue to fund highway improvements.

Del. James K. "Jay" O'Brien Jr. of Fairfax, Republican candidate in a special election for the 39th State Senate District, attended the anti-tax rally at Burke Lake, while his Democratic opponent, Rosemary Lynch, visited supermarkets in eastern Prince William County telling voters she was the pro-transportation-tax, anti-gridlock candidate.

Meanwhile, Republican leaders in Prince William linked arms with the county's Democratic officials for a get-out-the-vote effort to get the tax approved.

"This is our last-minute blitz to show our colors," Del. John A. "Jack" Rollison III, author of the law authorizing the referendum, said at the Woodbridge gathering in support of the tax.

Rollison and Clerk of the Circuit Court David C. Mabie exhorted many members of their traditional opposition -- Sheriff E. Lee Stoffregen III (D), Supervisor John D. Jenkins (D-Neabsco), Supervisor Hilda M. Barg (D-Woodbridge) and others -- to "come together to do something for this community" in getting out the vote.

And while Rollison praised the group for putting aside philosophical differences for the sake of better roads, he criticized Republican Del. Robert G. Marshall (R-Prince William) for distributing a newsletter that Rollison said was false and was designed to scare people into voting against the tax.

Specifically, Rollison took exception to assertions that the money raised would not stay in Northern Virginia and that many, if not most, of the projects would never be built.

The tax referendum has been a goal of the Northern Virginia delegation to the General Assembly for several years.

Gilmore, who has joined the law firm of Kelley Drye & Warren LLP and has a residence in Alexandria, opposed it, and it repeatedly failed to pass during his term. This year, the General Assembly approved a bill authorizing the referendum, and Warner signed it.

Gilmore said he decided to watch the debate over higher taxes unfold before taking a public stand.

When Warner took office in January, he said the six-year road-building plan he inherited from the Gilmore administration was in financial disarray and was committed to build dozens more roads than the Department of Transportation could deliver. Warner pronounced the plan a "fairy tale" and cut it by a third.

Yesterday, Gilmore said his successor has missed several opportunities to bring Virginia more road-building money. He cited the recent closing of a dozen Department of Motor Vehicles service centers that bring in revenue and VDOT's decision not to apply for $15 million in highway money available from the federal government.

"At first I thought it was just ineptitude, but now I'm beginning to think they wanted to starve the transportation system of money to impose maximum pain, so people will come and vote for a tax increase," Gilmore said. "Now Virginia's highway money is going to other states."

VDOT officials said they did not pursue the $15 million because the department did not have the required matching money from the state.

Republicans fighting the proposal for a regional increase in the sales tax rally at Burke Lake Park.State Senate candidate Rosemary Lynch backs the increase; her opponent, Del. James K. "Jay" O'Brien Jr., opposes it.