State Sen. Christopher Van Hollen Jr. overcame a significant fundraising disadvantage and the allure of the Kennedy name to defeat Del. Mark K. Shriver in Maryland's 8th Congressional Democratic primary yesterday.

Shriver, the nephew of President John F. Kennedy, far outspent the other three candidates in the race and benefited from election-day campaign help from organized labor. But Van Hollen emerged the victor by activating an ardent network of PTA members, environmentalists and gun-control advocates.

Van Hollen will now face eight-term incumbent U.S. Rep. Constance A. Morella (R) in a race that will help determine which party controls the House.

"I am confident if we unite we can win this race and take back this seat for the Democrats," Van Hollen said to a cheering crowd at nearly 1:30 this morning. "We are just six seats away from taking back control."

He praised Shriver for his campaign and for his gracious concession, which came in a phone call from home at around 1 a.m. Shriver did not make a public statement, but spokesman Jay Strell said "Mark has always said he would support the Democratic nominee."

First-time candidate Ira Shapiro, a Clinton administration trade negotiator, ran a spirited campaign but came in a distant third, promised to do "everything I can" to elect Van Hollen. Five-time congressional candidate Deborah Vollmer demonstrated little grass-roots support.

Trouble with Montgomery County's new, computerized elections machines prolonged the anxiety on all sides, as the night slipped into morning with scatter-shot reporting from precincts.

More than a year ago when the race began, the outcome would have been hard to predict. Shriver seemed a shoo-in, able to raise vast amount of cash through a national network of big-time Democratic donors.

But even before early turnout returns began to spook Shriver yesterday morning, the momentum was shifting Van Hollen's way as the state senator completed his sweep of local newspaper endorsements and began touting them in a television push. Shriver made a last stand yesterday in the heavily African-American precincts of Prince George's counts, calling in additional union help, but it wasn't enough.

Democrats have targeted the seat in their battle to retake control of the House, and Republicans from President Bush down have made protecting Morella a top priority. Already the most expensive House race in the country, the money is expected to continue to pour in on both sides.

Morella didn't bother waiting for the final results. As Democrats streamed out of the polls, her campaign was handing them a brochure highlighting Morella's endorsement by such traditionally Democratic-leaning groups as the League of Conservation Voters, the Brady Campaign to Prevent Gun Violence and the National Abortion Rights Action League.

The incumbent is widely considered one of the House's most vulnerable Republicans, despite her personal popularity and a record that makes her one of the most liberal Republicans in the House. In part because the Democratic-led Maryland General Assembly drastically redrew her district -- lopping off Morella strongholds in northern Montgomery County and moving it east into a heavily black sliver of western Prince George's County, Morella now faces the stiffest challenge of her political career.

Morella, though, has the advantage of sitting on her pile of cash -- she had nearly $1.7 million in the bank at last report -- while the Democrats hemorrhaged money in the down-to-the-wire primary race.

And although Democratic race remained civil by national standards, it is an open question whether the ardent grass-roots supporters of the losing candidates will be able to unite behind their nominee.

Three of the candidates -- Van Hollen, Shriver and Shapiro -- had the wherewithal to hire some of the best political consultants in the country.

They recruited armies of volunteers to knock on doors. They polled the electorate repeatedly, searching for exactly the right message for stump speeches and television commercials. They employed the latest in technology to target groups of potential supporters, then plied them with campaign mail and thousands of phone calls.

Early on, it became clear that there were few real issues separating the three. All favored rolling back the Bush administration tax cuts; the creation of a Medicare prescription drug benefit; increased federal education spending; stricter gun control and unfettered abortion rights.

Van Hollen argued that his broad legislative accomplishments showed he was best equipped. His slogan -- "a congressman for people who care about issues" -- was designed to appeal to an electorate that views itself as politically sophisticated.

That message resonated with Christina Brown, 44, of Rockville, who voted for Van Hollen after concluding that Shriver "has a good heart and has some good ideas, but he just didn't accomplish enough yet."

Shriver cast himself as the champion of the "voiceless," running a classic Democratic campaign in which he touted his labor endorsements, focused on the GOP's ties to big business, and vowed to take on the National Rifle Association, pharmaceutical companies and corporate wrongdoers.

Shapiro, hoping to tap into the post-Sept. 11 zeitgeist, offered himself to voters as the candidate with the most experience in national and international affairs. That experience brought him the endorsement of such luminaries as former vice president Walter F. Mondale.

Shriver began the race as the presumptive front-runner, given his huge fundraising and name recognition advantage. But he was unable to put the race away early, and the aura of invincibility that initially surrounded his candidacy slowly evaporated.

For months, his campaign was hyper-sensitive to suggestions that Shriver was trading on his family name. But in the final push, it sought to remind voters of the advantages that name brings with it in a pragmatic appeal to hard-core Democrats bent on ousting Morella.

Shriver also moved to capitalize on his family's celebrity appeal in the final weeks of the campaign. In literature, he quoted the late president. At Metro stops, he stumped with his uncle, U.S. Sen. Edward M. Kennedy (D-Mass.). On primary election day, he sent his mother, Eunice Kennedy Shriver, and sister, "Dateline NBC" anchor Maria Shriver, to the polls.

Just blocks from Van Hollen's Kensington headquarters, Tom and Beverly Fischetti emerged from a library where both had cast votes for Shriver.

"Although I was impressed with Van Hollen's record, I just decided that I thought Shriver was the only chance to beat Morella," said Tom Fischetti, 58.

Hoping to suppress Van Hollen's vote in the aftermath of endorsements by The Washington Post and the Baltimore Sun, Shriver accused him of going negative.

Both camps were receiving nearly minute-by-minute turnout updates yesterday.

Van Hollen field coordinator Josh Bushey was plugging the numbers into a computer projection program as fast he could, feeling good as he reported to Jost about 11 a.m. "We're over halfway there in Chevy Chase," he exclaimed. "The base is movin' -- yeah, buddy!"

Meanwhile, low turnout figures prompted the Shriver campaign to issue a round of calls, urging union employees to head to Prince George's to help turn out the vote. The unions, stretched thin because they were also working on behalf of D.C. Mayor Anthony A. Williams (D), redeployed bodies for a "knock and drag," as in knock on supporters' doors and drag them to the polls from 4 to 8 p.m. As Willie Harris, regional political director for the Service Employees International Union put it, "It was time to call in the troops."

In other Maryland congressional races, Baltimore County Executive C.A. Dutch Ruppersberger defeated investment banker Oz Bangur, and will compete against Helen Delich Bentley in November.

In District 1, incumbent Rep. Wayne Gilchrest beat back a challenge from the Republicans' conservative wing.

Democratic Rep. Albert R. Wynn easily won the Democratic nomination in the 4th District, and Republican John B. Kimble was leading the field of possible Republican opponents. Democratic Rep. Steny H. Hoyer had no competition in the 5th District. He will face Republican activist Joseph T. Crawford in the November election.

Staff writers Michael E. Ruane, Phuong Ly and Chris Davenport contributed to this report.

Del. Mark K. Shriver, who later called Van Hollen to concede, returns to his room after speaking to a crowd of supporters. "I am confident if we unite we can win this race and take back this seat for the Democrats," Van Hollen told supporters. State Sen. Christopher Van Hollen Jr. greets supporters at the Audubon Naturalist Society headquarters in Chevy Chase.