The candidates vying to represent Northern Virginia's heavily Republican, but fast-changing, 10th Congressional District have hit each other with a series of personal attacks that reflect an unusual level of competitiveness in a district that has been won by the same man in each of the past dozen elections.

Democrat James R. Socas has run an aggressive campaign to unseat 12-term GOP incumbent Frank R. Wolf. Like Wolf, Socas has tried to appeal to voters with promises to address mainstay issues such as snarled traffic. Both candidates have veered into questions about their opponent's fitness for office. Socas says that Wolf is a right-wing religious extremist out of touch with the concerns of a moderate district. Wolf says that Socas is an ill-informed newcomer with little commitment to a district he moved into just last year.

Their approaches have been shaped by their starkly different backgrounds.

Socas, 38, amassed a fortune -- between $7 million and more than $20 million, according to federal campaign filings -- as a technology guru and investment banker for Credit Suisse First Boston and other financial institutions, and spent a year as an aide on the Senate Banking Committee. Those experiences, he said, left him focused on how to prepare U.S. workers for the new global economy and disappointed in the lack of analytical rigor he found on Capitol Hill.

Wolf, 65, has spent more than two decades as one of Congress's leading advocates for human rights around the world, with an emphasis on religious persecution, and has also taken on issues including terrorism, FBI reform and local street gangs during a career that he said demonstrates an approachable style and a willingness to work with colleagues and officials in both parties to get things done.

The district covers a wide stretch of Northern Virginia, running west from western Fairfax County, across northern Prince William and Fauquier counties, and including Loudoun, Clarke and parts of Warren and Frederick counties, plus the cities of Manassas, Manassas Park and Winchester.

One of Socas's signature proposals is a two-pronged effort to increase the number of Americans who attend college by, first, guaranteeing that freshman-year tuition at any state college would be covered for students who spend 10 hours a week doing community service or working a part-time job. He also calls for tripling, to $12,000, the allowed tax deduction for college tuition. Together, the cost of the proposals would approach $12 billion annually, he estimates.

Socas, at the same time, has slammed Wolf and others in Congress for soaring budget deficits and the mounting national debt, saying Wolf has helped saddle each child born in the country this year with a $25,454 "toddler tax," calculated as each individual's share of the national debt.

Socas also has accused Wolf in campaign materials of voting against breast cancer research funding and being "anti-women."

The funding proposal Socas refers to, from the early 1990s, was part of a bill on a broader question: whether to allow research on fetal tissue, which Wolf opposed. Wolf, whose parents both died of cancer, said he has been a strong proponent of increased spending. "We've doubled the funding in the last five years for the National Institutes of Health," upping funding for research into all forms of cancer, Wolf said.

Wolf has seized on his opponent's proposals, pointing to what he says would be an exorbitant price tag for the tuition measure. Socas, he said, can't have it both ways -- proposing a big new spending program while preaching fiscal restraint.

Socas said that it is a fundamental misunderstanding to argue that his education plan represents costly new spending.

"I'm so tired of hearing that. I've worked in the markets. It's such a load of baloney," Socas said, adding that the United States' strong point in global competition has, and should continue to be, the "human capital advantage." His education proposal will pay for itself because the government will net higher proceeds from the increased earning power of more-educated taxpayers, Socas said.

The candidates diverge on social issues such as abortion. Wolf opposes legal abortion; Socas supports it. Socas says Wolf has been distracted by "extremist" causes, such as efforts to tighten rules on gambling and to pass a constitutional amendment banning same-sex marriage. "I think it's a disgrace we take days out of the congressional agenda to debate things that only serve to divide this country," Socas said.

Wolf argues that such issues have bipartisan support.

"We have not polarized the region at all," Wolf said, adding that Socas is the one out of touch with the local community. "You have a guy who has a lot of money, no record," he said. "He doesn't own a house here. He owns a house in California."

Socas rents his home in McLean, saying it doesn't make sense to buy into a real estate market at its peak.

Both men promise they would work hard to find funding to reduce the congestion that has slowed commutes as the region has expanded. But transportation experts argue that limited federal funds alone will not solve area traffic woes, which they say have been made worse by the combination of swift, scattered development and a dramatic under-funding of roads and other transportation improvements.