Senate candidate George Allen has expanded the Republican fund-raising network that fueled his successful 1993 run for Virginia governor, building a grass-roots organization for 2000 that has far outpaced the campaign of his Democratic rival, Sen. Charles S. Robb.

Federal Election Commission reports for the first half of the year show Allen successfully switching from Virginia's wide-open campaign finance system to the federal limit of $2,000 on individual gifts. He expanded his base of support 20 percent beyond what it was when he was governor from 1994 to 1998 and reached 6,549 individual donors.

Allen raised $2.5 million during the six-month period and had $2.3 million in cash on hand after expenses. Robb raised $1 million for his campaign and had the same amount on hand. Both men smashed fund-raising records at this early stage of a Virginia Senate race, with Robb out-performing his 1994 reelection effort.

Robb has leveraged his power as a two-term incumbent to draw funds from political action committees and national givers from San Francisco to Austin to Miami, Democrats noted, and he has barely begun to tap his loyal Virginia donors.

About 65 percent of Robb's individual contributions came from outside Virginia, as did 90 percent of his PAC contributions. Allen has tapped Virginia for 83 percent of his individual gifts, as well as 35 percent of his PAC money.

Fund-raising experts said Allen's broad show of strength and Robb's deep pool of resources foreshadow a marquee race that will be watched across the country.

Sen. Robert G. Torricelli of New Jersey, the Democratic Senatorial Campaign Committee chairman, has said the defense of Robb's seat is his top priority. But Allen also starts with advantages: a united Republican Party, a lead in the polls in the low double-digits and the massive financial edge.

"Everybody says it's early, just wait--but the fund-raising numbers and the poll numbers are not much short of unprecedented," said political analyst Stuart Rothenberg. "You have a sitting U.S. senator who's out-raised by more than 2 to 1. . . . He [Robb] has got to take the race to the governor really hard."

Jay Timmons, Allen's general campaign consultant, said Allen flooded contributors with three mailings before the June 30 reporting deadline to build credibility. "The response was exhilarating--it took us by surprise," Timmons said.

Allen is also benefiting from party unity. Unlike Republican Oliver L. North's fratricidal 1994 Senate bid in which GOP moderates bolted and a third-party rival emerged, Allen's 2000 campaign is co-chaired by Sen. John W. Warner (R-Va.); one of his mail consultants was fund-raising director for Gov. James S. Gilmore III (R); and donors include social conservatives, as well as Northern Virginia backers of his 1993 primary rival for governor, Earle C. Williams.

National and congressional GOP leaders have embraced Allen as they attempt to hold onto control of the Senate. He took in PAC gifts of $10,000 from Senate Majority Leader Trent Lott (Miss.), $5,000 from Sens. Mitch McConnell (Ky.), Don Nickles (Okla.) and Rep. John A. Boehner (Ohio), $2,000 from New York Gov. George E. Pataki and lesser amounts from New Jersey Gov. Christine Todd Whitman, Rep. Deborah Pryce (Ohio) and Rep. Jennifer Dunn (Wash.).

Other donors included retired Gen. Colin L. Powell, Pat Robertson, Marvin Bush, the brother of GOP presidential candidate George W. Bush, and telecommunications, finance, tobacco and industrial PACs.

Robb aides and supporters, and Robb himself, dismiss Allen's showing. Robb, a member of the Armed Services and Select Intelligence committees, forswore heavy fund-raising and focused on Senate duties during last winter's impeachment trial and NATO's 11-week bombing campaign against Serbia.

Robb backers add that he was outraised 4 to 1 in 1994 by North, but still won with 46 percent of the vote, continuing his unbeaten streak in four statewide elections.

"I'm the only one [Senate Democrat] at this point who has . . . a first-tier challenger, so everybody gets to fill up blank space in the paper with prognosticators," Robb said confidently this week in Arlington, where he and business leaders pushed for Northern Virginia road and transit funding. "I've been up, I've been down, I have some sense of timing, and I'll just leave it at that."

In his first appeal to 14,000 supporters in late June, sent too late to be reflected in financial reports, Robb telegraphed that his campaign message would be about fiscal conservatism and social moderation, not fund-raising, about "solutions, not sound bites."

Still, several Democratic fund-raisers acknowledged some business givers are nervous about giving to Robb because of successive Democratic defeats since 1993.

So far, Robb's strategy has been to go after national contributions before next year's presidential campaign becomes all-consuming, and not to compete with Virginia Democrats who are raising funds for legislative elections this fall.

His donors include PACs run by Senate Minority Leader Thomas A. Daschle (S.D.) ($2,000, plus $16,500 from the DSCC) and Sen. John Breaux (La.) ($9,999), and 1996 Virginia Senate candidate Mark R. Warner ($2,000) and former lieutenant governor Donald S. Beyer Jr. ($2,000).

Robb also has shored up his support among technology executives, winning the support of America Online Chief Executive Steve Case, President Bob Pittman and Chief Technology Officer Marc Andreessen, and heads of information technology and computer industry associations.

Other givers to Robb include labor unions, Republican former defense secretary Frank C. Carlucci, Fairfax developer John T. "Til" Hazel Jr., Black Entertainment Television executive Robert Johnson, Baltimore Orioles owner Peter Angelos and Washington Wizards owner Abe Pollin.

CAPTION: In April, George Allen announced his run for the U.S. Senate in 2000 against Democratic Sen. Charles S. Robb. This year, Allen has raised $2.5 million.