Democrats and Republicans are mounting aggressive campaigns to win House of Delegates seats in Northern Virginia by invoking last year's state tax package, as Gov. Mark R. Warner's signature program continues to reverberate in state politics.

In taking on incumbent delegates, Democrats are highlighting Republicans' opposition to the 2004 budget package that funded education, health care and public safety initiatives. Republican candidates are arguing that the tax package was bad for Northern Virginia because it didn't bring home money for transportation projects and the region does not receive an equitable share of the revenue raised.

All 100 House of Delegates seats statewide are up for election this year.

Democratic leaders said they think the popularity of the initiatives, as reflected in several statewide polls, gives them a powerful message to run on in the Washington suburbs.

A Washington Post poll conducted Sept. 6 to 9 found that the budget plan backed by Warner, which will raise $1.5 billion over two years, is supported widely.

"It's not a coincidence," Del. Brian J. Moran (D-Alexandria), chairman of the House Democratic Caucus, said of the party's campaign theme. "These are some of the members who most aggressively and most vigorously opposed the budget reform package."

The package was passed after 17 House Republicans joined with Warner and the state Senate to support the tax increases. Only one of the mavericks, Harry J. Parrish (R-Manassas), is being challenged by Democrats in the Nov. 8 election.

Democrats in Northern Virginia are targeting Dels. Richard H. Black (Loudoun), David B. Albo (Fairfax) and Robert G. Marshall, Jeffrey M. Frederick and Michele B. McQuigg (all of Prince William). For Albo, Marshall and McQuigg, it's the first challenge they have had in several election cycles, according to state records.

Several Northern Virginia Democratic candidates said Republican opposition to the tax package would be central to their platforms. Others said their foes' opposition was out of step with their districts.

"I'm running because of my opponent's ineffectiveness in office, and his failure to support last year's budget reform is certainly a piece of that," said David Poisson, who is challenging Black, one of the General Assembly's most conservative members. Democratic sources who spoke on condition that their names not be used said party polls have Poisson within striking distance of the four-term delegate.

Republican incumbents countered by pointing out that the tax package did not include money for road and rail projects. Indeed, of the $1.5 billion raised, hardly any was spent on transportation.

Republican challengers are using the same argument in races against incumbent Democratic Dels. Stephen C. Shannon, Mark D. Sickles and Vivian E. Watts, all of Fairfax.

In the Post poll, 89 percent of registered voters said transportation was an important issue in deciding how they would vote in the governor's race.

"There was nothing, not a penny in that budget that was brought home for transportation projects," Black said. "All the liberals said: 'My goodness, the sky is going to fall without transportation money.' . . . That's what I thought this whole deal was about."

James Hyland is challenging Shannon for supporting a tax package that Hyland said did not bring enough transportation money to the 35th House District. "Steve Shannon should not have raised taxes, and he should have fought to get our fair share for transportation and education like he promised," Hyland's Web site says.

"For Northern Virginia," Hyland said in an interview, "it was a terrible deal."

Shannon said the 2004 tax package helped set the stage for this year's legislative decision to increase transportation funding. He said Virginia was able to fund $848 million in transportation initiatives in 2005 largely because it got its finances in shape in 2004.

"The people in my district are smart," Shannon said. "They know that the anti-tax, anti-property-tax message doesn't have legs anymore."

The tax issue is also likely to be prominent in Northern Virginia districts where no incumbent is running. Democrats supportive of the plan are running against anti-tax Republicans in those districts.

In the 41st District in Fairfax County, Democrat Dave W. Marsden faces Republican Michael J. Golden. In the 67th District in Fairfax and Loudoun counties, Democrat Chuck Caputo faces Chris S. Craddock, who defeated Del. Gary A. Reese (R-Fairfax) in a June primary. Chuck J. Eby Jr., a Libertarian, also is running in the 67th.