Virginia state Del. Frank Medico patted the sweat off his brow as his opponent attacked him for everything from dishonesty to ineffectiveness to being partially responsible for the unnecessary maiming of small children.

"It's unfortunate he's getting into a negative campaign, which I despise," Medico said when his turn came to address the small group of Mount Vernon social workers and mental health therapists. "It's easy to pick a bill and say, you didn't do this and you didn't do that . . . .It's easy to sit up here and make judgments, but you had to listen to the evidence."

Fairfax Republican Medico and more than a dozen other Northern Virginia legislators are finding themselves in unfamiliar and frequently uncomfortable positions this year: they are having to defend their records. Fairfax County, which not long ago was represented by 10 delegates who ran in a pack, this year was carved into 12 separate districts in which incumbents must face their opponents one-on-one.

For Medico, an amiable 58-year-old accountant who resembles Ronald Reagan with a New England accent, the redistricting has meant a tough and unusually direct challenge from Democrat David L. Temple, a sharp-tongued, quick-witted Fairfax school principal. Temple has forced Medico to defend his attendance (he went to every House session but missed some votes), his accomplishments (none of his bills was approved) and his stand on a bill to require children to wear seatbelts in automobiles (he didn't vote on it -- thus the maiming charge).

Medico, elected in his first try for office a year ago, is considered by many county politicians to be among the more vulnerable of Fairfax incumbents in the Nov. 2 elections for a one-year term in the House of Delegates. But most say he holds an edge over Temple, now mounting his third consecutive campaign for public office. Temple, a black in a 94 percent white district, must contend with Medico's familiarity after a decade of civic involvement and with the Republican's success at salvaging a reasonably friendly district from last year's redistricting battles.

Medico's 44th House District includes gracious estates along the Potomac River, asphalt trailer parks along Route 1 and established suburban neighborhoods in between. About half the district's voters are regarded as independents, with the rest evenly split between parties, making the 44th a genuine swing district. Medico was almost stuck with a less friendly district but managed at the last minute to unload several largely Democratic precincts into the neighboring 43rd, where they were warmly accepted by incumbent Democratic Del. Gladys B. Keating.

Both Medico and Temple are working hard, knocking on doors day after day, each in his own way accustomed to long odds and long hours. Medico is a former ditch digger from South Braintree, Mass., who spent eight years in night school to work his way up from a GS-2 government clerk with a high school diploma to an assistant director of the General Accounting Office. He resigned on his 55th birthday to concentrate on civic and political affairs.

Temple grew up in Richmond, was arrested at age 16 for sitting at an all-white lunch counter and entered the University of Virginia as one of five blacks in a class of 1,300. The principal of Lincolnia Vocational Center, a public school for retarded and handicapped youth aged 16 to 22, Temple would be the first black to represent Northern Virginia in the General Assembly, at least in this century. Five of the legislature's 140 members are black, but none represents a suburban or predominantly white district.

"A part of the referendum for me, the third time out, is whether a qualified black person, a qualified person who has worked hard and is dedicated to the broad stripe of the community, can in fact convince the majority of the electorate that he can represent their interests," Temple says. "Particularly when the incumbent is so woefully inadequate."

If race is a factor, however, both candidates say it is not an issue. The issues are experience, credibility and the record, they say, and Temple is hitting the issues hard. "I'm sorry, Frank," he said during the discussion at the Mount Vernon Mental Health Center. "It's a bankrupt incumbency."

Medico says he doesn't know how to rebut Temple's charges without sounding defensive or engaging in the same kind of "negative" campaigning he deplores. When Temple mentions the missed votes, Medico says he didn't have time to read some bills and didn't consider others critical to his district. "I don't care about the gigging of fish in Russell County," he says. "That's a local problem."

When Temple accuses Medico of falling short on women's issues -- he voted against Medicaid funding for abortion in cases of rape, incest and fetal abnormality; against bringing the Equal Rights Amendment to the floor for a vote; and against increasing marriage license fees to pay for shelters for battered spouses -- Medico seems personally wounded.

"I had two black gals as secretaries at GAO , they were upward mobility types," he says. "I got them into the professional ladder, I used to make sure they got into school if they wanted . . . . I had five or six black women who asked to be at my retirement party , one cried when I left. Why? Because I was compassionate and I cared and they wanted to better themselves and I helped them to do that . . . . Now does that sound like a guy who's anti-woman?"

Mostly, Medico -- like many other House incumbents this year -- says the negative charges will only hurt his opponent. Temple presses on.

"I think it is my responsibility to make sure people know his record, because I can't imagine he is either proud of it or able to explain it or willing to explain it," Temple says. "If I go down, at least I'll have the satisfaction of knowing people made a choice having full knowledge."

Del. Warren Barry, a longtime Fairfax Republican who this fall finds himself the unaccustomed object of an unusually personal campaign by teacher Mark Glaser, said the new, single-member districts have intensified the mud-slinging. "Of course," he says, "the truth of the matter is that when I first ran, I took some shots at the incumbents myself."