During their first debate, the challenger was tarred as Big Oil's bedfellow and accused of conflict of interest. The incumbent was blamed for the nation's economic chaos and charged with political deceit. The Democrat growled at the Republican who bared his own partisan teeth.

"They're going to get into a fist fight before this (campaign) is over," said Jane Paris, whose husband Stan is fighting to win back Virginia's 8th congressional district seat from Rep. Herb Harris, who has successfully defended it twice since upsetting Parris in 1974.

The fight between Harris, a liberal Democrat, and Parris, a conservative Republican, has struck vengeful sparks in Virginia where campaigning is traditionally more genteel. They are not only competing candidates but ideological warriors crusading for the might of right and left.And neither man likes the other even a little.

"I did not expect to see two grown men pummeling each other," says independent Deborah Frantz, 25, the third candidate in the race to represent 464,000 voters in Alexandria and Prince William, southern Fairfax and northern Stafford counties.

Part of the intensity can be understood in the context of this year's presidential campaign. Republicans read Reagan's popularity polls in Virginia and conjure a vision of Parris riding those coattails to victory over Harris, whom Republicans malign as one of the most liberal congressmen in Virginia.

The Democrats are aware of the same polls. And after the surprising gains made by the GOP in last year's General Assembly elections, Northern Virginia Democrats are loath to let their opponents gain any more political ground, particularly in an area that has generally been considered a liberal stronghold.

"This is a classic confrontation," says Nick Panuzio, the former head of Fairfax County's Republican party. "You've got a liberal and a conservative who are both very strong fighters. It will be a tough one."

The animosity between Harris and Parris predates their 1974 contest. Ten years earlier the two met on opposite sides of local Fairfax County issues. Harris was the president of a coalition of civic associations. Parris was a zoning attorney. Both built strong enough political bases to be elected to the county's board of supervisors, though at different times.

By the time Harris challenged Parris for his congressional seat, each had developed a distaste for the other's political stripes. Parris now blames his loss in 1974 on both the political fallout after Watergate and his own tactical blunder. Parris says he was persuaded during that campaign to stand behind his incumbency, present his best Virginia gentleman profile and let Harris throw all the punches.

"I took the high road and it was a mistake," he says.

Harris officials have a different recollection of that campaign. Linda Golodner, the Harris campaign manager, says Parris' downfall "was his own record."

Virginia Republicans are now confident that the political tables are turned -- that Carter will be a liability for Harris who now has his own record to defend.

But Harris won't accept that Republican version of coming events. In 1976, he points out, Gerald Ford carried Virginia while Harris won reelection with more than 50 percent of the vote in a three-way race.

Presidential politics don't translate in Northern Virginia," says Harris, a 54-year-old with the face of a Boston Irish ward leader. The 51-year-old Parris, in what seems a particularly appropriate contrast, has the white-haired patrician look of a Connecticut vicar.

Deborah Frantz, the independent, is a political rookie whose primary issue is the repeal of all marijuana laws. Parris thinks she'll hurt Harris, who isn't sure what effect she'll have. But neither candidate seems particularly alarmed.

"She'll provide the half-time entertainment while Harris and Parris lick their wounds," said one.

The Republicans are taking aim at Harris where they consider him to be most vulnerable -- his votes on defense appropriations and, as Parris puts it, "The crackpot, liberal, harebrained scheme[s]" Harris has supported.

Two weeks ago the Parris campaign released the first radio ads in a $200,000 media blitz. Prepared by Bailey Dear-dourff and Associates, the same advertising agency that handled Gerald Ford's 1976 presidentail campaign, the ads are a velveteen dagger aimed at the jugular.

In one of four new ads released this week, titled "Hide and Seek," a little girl's voice counts ". . .98. . .99. . .100" before telling "Congressman Harris" that she's coming to find his voting record, ready or not.

As the campaign continues, there will be more ads, including 60-second television spots touting a fictitious "Incumbent Show" where congressmen try to hide their voting records. Thousands of undecided voters, identified through phone banks, will be sent "Incumbent Game" boards similar to Monopoly. Finally, in the last week before the election, signs will be planted on lawns all over the district advising, "Stop the Game."

Harris denies that he is either soft on national defense or strong on spending. From a file in his congressional office he produces a two-page list of military appropriation bills he has voted for in the past two years. On the subject of nonmilitary spending, he says he sponsored a bill to curb year-end spending sprees in the House.

"The notion of spending $200,000 on a media campaign is very worrisome," says Harris, taking the offensive. "Too many people are aware of what's going on. The district cannot be bought."

Parris campaign officials sneer that Harris does not need to spend as much for media because he can send thousands of dollars worth of free newsletters to all his constituents.

Harris landed the campaign's earliest punches two weeks ago during the candidates' first radio debate. He accused Parris of voting during his two-year term in Congress "to promote the interests of the oil companies" and of having as "conflict of interest because of your hundreds of thousands [of dollars] of stock" in major oil companies.

Parris conceded that he owns approximately 1,200 shares of Texaco, Mobil and Phillips Petroleum stock. But Parris said the stock was purchased after he left Congress and would be placed in a blind trust if he is elected.

"That's a smokescreen," complained Parris. "He's trying to create anything to keep from talking about his record."

Harris denies that Parris has him scared. Jack Herrity, the Fairfax County Board of Supervisors chairman who challenged him two years ago, was "tougher," says Harris.Besides, says the three-term incumbent, he thinks he knows what to expect and when from Parris.

"We've been in the ring before."