NOT LONG ago a group of downstate visitors, one wearing a "Harvey Gantt for Senate" T-shirt, entered a remote backwoods store in Ashe County, near the New River in the northwest corner of North Carolina.

The mountains of North Carolina are Lincoln Republican turf, and the store owner eyed the T-shirt warily at first. Then he spoke.

"Your man is lookin' whiter and whiter every day," he opined in a deep Southern drawl. "There must be no more than 20 {blacks} in this whole county, and Gantt's gonna get two-thirds of the whole vote."

Why would white Southern Republicans vote for a black Democratic candidate?

"Anybody's better than Jesse," the owner replied.

Many Democrats thought the last best chance to beat Jesse Helms was in 1984, when he squared off against Gov. Jim Hunt; or in 1978, before Luther Hodges Jr., son of a former governor and chairman of the North Carolina National Bank, lost the primary; or in 1972, when Helms was first elected to the Senate on a campaign slogan, "Jesse -- he's one of us," that played on the foreign-sounding name of his opponent, Nick Galifinakis.

For years, the conventional wisdom has been that only a candidate with a strong political base in the conservative Democratic eastern region of North Carolina could beat Helms. Such a candidate, the idea went, could win by attracting black voters and more moderate whites from the state's more populous Piedmont region too.

The Democrats had such a candidate in 1990 in Mike Easley, a young district attorney from Wilmington. Just 39 years old, Easley earned a hero's reputation down East for prosecuting drug kingpins who had threatened his wife and children. Harvey Gantt, the black former mayor of Charlotte, surprised many by beating him 57 to 43 percent in the primary run-off last May.

Running against Helms with a candidate whose only political credentials were two terms as a member of the Charlotte City Council and two as mayor may have seemed dubious to Democratic Party regulars. Running a black candidate who opposes the death penalty probably seemed like political suicide. Gantt has held no political office since 1987, when he was defeated for reelection as mayor by a Republican woman with scant political credentials. His runoff victory in May owed more to high black turnout than to Gantt's ability to tap into mainstream North Carolina concerns.

But the day after the runoff, Gantt took Helms's basic message and fired it right back. Carter Wrenn, the executive director of the Congressional Club, the fund-raising arm of the Helms campaign and a top Helms strategist, said, "What you have opposing Helms is another coalition of homosexuals and artists and pacifists and every other left-wing group."

Gantt replied that that kind of statement "reflects more on the person who said it than anything else." The Gantt camp accomplished two vital things before Labor Day, however. First, it quietly consolidated its black voting base. Helms had the summer airwaves to himself, running spots that heavily invoked George Bush. (Bush skipped an international AIDS conference to attend a $1 million Helms fund-raiser in Charlotte, where he told the crowd, "I need this man.") But meanwhile, Gantt organized black churches and black leadership in the state. Unlike Hunt's campaign in 1984, when Jesse L. Jackson made much-publicized voter registration visits to North Carolina that mobilized the Christian Right and provoked a white backlash, Gantt's effort was very low-profile. Jackson and other black politicians have reportedly been asked to stay out of North Carolina for this race.

Second, the Gantt campaign forged ties with the Mike Easley wing of North Carolina's Democratic Party. In August, Easley's campaign manager was asked to become deputy manager of the Gantt effort. Democrats in the state outnumber Republicans 64 to 31 percent and control both houses of the legislature, but the governor and lieutenant governor are both Republicans. The Democratic Party rank and file, eager to reassert statewide power, welcomed the overture.

Gantt had much to gain from a short, focused campaign, and came on strong after Labor Day. A number of factors are working in Gantt's favor. The candidate himself has proved a highly charismatic stump speaker and has drawn thousands of students to rallies with a 1960s fervor. Helms, on the other hand, who started ahead in the polls, refuses to debate Gantt -- unlike 1984, when he played catch-up and debated Jim Hunt six times. The senator, always a reluctant campaigner, now insists that reporters communicate with his campaign by fax. He is portrayed, at least in his non-attack advertising, as a kindly Uncle Jesse. In fact, he turned a grandfatherly 69 last week and looks puffy and paunchy. Gantt, at 47, looks distinguished and energetic.

There are a number of striking differences between this race and the Helms races of 1972, 1978 and 1984. In 1972 and 1984, when Helms faced strong opponents, he rode the coattails of Richard Nixon and Ronald Reagan (who outpolled him in North Carolina). John Ingram, his 1978 opponent, ran as an outsider and raised a paltry $300,000 compared to Helms's $7.5 million. This time Helms faces a candidate with good funding (Gantt raised $3.2 million to Helms' $3.4 million between June and September and is spending $300,000 a week on TV ads), statewide Democratic support, a Baptist preacher's intensity and few political liabilities in the form of an existing record to hammer on.

That Gantt is dead even with Helms in the polls is the big story of the race so far. Gantt has impressed most local observers with his ability to make Helms run on his record. Both sides have staked out tactical positions and are scoring points on the issues: Helms on taxes, the death penalty and abortion; Gantt on abortion rights, education and the environment. But by October 1984, Helms controlled the campaign agenda and was pulling away. This year the agenda is up for grabs. That's why, despite the litany of charges aired in radio and TV ads, the campaign has seemed more like a chess match or fencing contest than a down-and-dirty brawl. The race is still tight as a tick. Barring a major misstep by either candidate or an "October surprise" (like a Persian Gulf war), the outcome will depend on two factors over which Helms has limited control -- black registration and voter turnout.

North Carolina blacks make up about 20 percent of the state's population. Among registered voters blacks, as of last April, lagged slightly behind at 18.25 percent of the total. The Gantt effort has produced significant change, however. Oct. 8 was the deadline to register for the Nov. 6 election, and Mecklenburg and Wake counties, the most populous in the state, reported an increase of more than 10 percent in new black voters. White registration increased by a much smaller percentage (3 percent) but a larger absolute number. However, many of these white registrants are likely Gantt voters. For example, in Wake County, where Raleigh is located, new Democratic registrants outnumbered Republicans 4,700 to 1,900.

If this pattern holds up statewide -- and indications are that it has -- black voters now number 19 percent of the total. Neither Gantt nor Helms has made a campaign issue out of race, but the outcome in North Carolina will depend largely on that. The polls show Gantt getting more than 95 percent black support. If 80 percent of eligible black voters turn out on Nov. 6, and 19 of 20 vote Democratic, Gantt will get 14.4 percent of the statewide total right there. The conventional wisdom that Gantt needs 40 percent of the white vote to win is already dated. If whites voters turn out at only a 65 percent rate, Gantt may need as little as 37 percent of the white vote to win. (A recent poll showed him getting 35 percent, with 8 percent undecided.)

That's why Helms, in the final two weeks, may abandon current campaign protocol and try to make an issue out of race. He can't do it publicly without risking a backlash, but Helms has used rhetoric with cunning to get his message across in the past. "Block vote" has always meant "black vote" in the Helms lexicon.

Helms needs the race issue to motivate his own core constituency. There's no doubt about where it is concentrated. Ten less-populated counties in and around the state's Piedmont Crescent contain the potential white "block vote" for Helms. These key counties -- Alamance, Cabarrus, Caldwell, Catawba, Davidson, Gaston, Iredell, Randolph, Rowan and Wilkes -- delivered 98,000 more voters to Helms than Hunt in 1984, 12,000 more than Helms's total statewide margin. They make up 16 percent of the statewide total, with mostly non-union, blue-collar voters in textile mills and furniture factories near towns like Burlington, Statesville, Kannapolis, Gastonia and Asheboro.

This is the bread-and-butter Helms constituency. It dislikes "art" and homosexuals, resents foreign competition and tends to vote as much out of anger as economic self-interest. No national Democratic candidate had reached these voters since 1964, and despite Gantt's vocal opposition to a state hazardous waste facility that has made voter preferences in Iredell, Rowan and Davidson counties extremely volatile, Gantt is not likely to do so in 1990. Unlike most of the rest of the state, voter registration in these 10 counties is more than 90 percent white.

How many non-union, blue-collar white workers in Gaston County will vote in a non-presidential year? How motivated will they be when Ronald Reagan is not leading the charge, and when George Bush, to whom Helms has hitched his wagon, has done an about-face on taxes and led North Carolina and much of the rest of the Southeast into an economic "down" year?

Most important, how much do they fear the fact that Gantt is black? To most voters Gantt comes across not as black, but as self-confident, intelligent, even aloof. He has warmed considerably during the campaign, but there are still many whites in North Carolina who will find it very difficult to vote for him. For every "ignorant redneck" (as Helms recently termed his constituency in a Senate speech) who says, "Your man is looking whiter and whiter every day," another will say, "Son, I just can't vote for a black man."

Eighty percent black turnout would be very high, but Gantt may have the power to produce it. Whether Gantt needs 37 or 41 percent of the white vote to win will depend on how many of Helms's whites turn out -- and that may depend on how hard Helms plays the racial card. It's Helms's race to lose, and he cannot be comfortable about the outcome. In this David-and-Goliath contest, the big surprise could be that Harvey Gantt, who doesn't run on race but who can count on a big black vote, will be the Helms killer. It would be an ironic victory. If Gantt wins he'll not only defeat the most successful old-school Southern politician of the last 18 years, he'll be the first black Democrat ever elected to the U.S. Senate, and the first black Southern senator since Reconstruction.

Huntington Williams, the author of "Beyond Control: ABC and the Fate of the Networks" and the founding editor of the Gannett Center Journal, grew up in North Carolina.