They came in ox-drawn wagons, fleeing the yoke of the British Empire, hauling their Bibles, carbines and children into an uncharted wilderness populated by wary, often hostile African tribes.

Those who survived -- and many did not -- believed themselves a chosen people and this their Promised Land. They settled on these sweeping plains under the big sky, formed an all-white republic and consecrated their covenant with God by naming this town Bethlehem and the stream that runs through it the Jordan River.

More than a century later, the spirit of righteous certainty that ruled the lives of that pioneer generation of whites known as Afrikaners is fading for many of their heirs. Growing resistance from the long-fettered black majority, international opprobrium and economic malaise are adding to the sense that whites are losing control, that the years of ascendancy and privilege may be coming to a close.

"There is a lot of fear in the Afrikaner's heart," said Dolf Brits, a Dutch Reformed minister here. "It's not easy to admit we're going the same way as Rhodesia," South Africa's formerly white-ruled neighbor that became black-ruled Zimbabwe in 1980 after a prolonged civil war.

That anxiety was reflected dramatically last week when Afrikaners, who for at least two generations loyally have supported the ruling National Party by a vast majority, split almost evenly between the party and its growing right-wing opposition in the first by-elections since the government declared a state of emergency last July.

Although the electoral stakes were small -- just five seats in the main, 178-member, whites-only body of Parliament, of which the Nationalists held onto four -- the results set off alarm bells in Pretoria.

Despite promises from Nationalist leaders that the vote would not affect the government's program of limited change, it seemed almost certain to retard further a process most blacks already find painfully slow.

To understand why the loss of one parliamentary seat and a reduced victory margin in four others throws such a fright into South Africa's white rulers, it is instructive to venture into a small farming town like Bethlehem, whose white population of 15,000 is 90 percent Afrikaner.

Tucked into the heart of the Orange Free State, a traditional stronghold of Afrikaner conservatism, Bethlehem was one of the five districts up for grabs last week. The Nationalists held onto it, but by a much smaller margin than in the past.

Modern Afrikaners are the heirs of Dutch, French and German Protestants who began settling Africa's southern tip in the 17th century. Their ties to Europe gradually unraveled as they developed their own African-tinged vernacular and culture. Today they make up 60 percent of South Africa's ruling white minority, and unlike the white colonists who returned to Europe when the rest of Africa gained independence, for the Afrikaner there is no going back.

History for them is not an academic subject but a living organism that casts a large shadow. Not far from Bethlehem a visitor still can glimpse the remains of stone farmhouses destroyed by the British during the Boer War at the turn of the century. Many here boast ancestors who fought in that conflict, and many have family members who died in the British concentration camps that claimed the lives of 26,000 Afrikaners.

Bethlehem's Afrikaners say they no longer hate the British, nor the English-speakers who make up most of the remainder of South Africa's white minority. But while they may forgive, they do not forget.

They have proved even more unyielding with another traditional foe -- the blacks who fought them in six tribal wars in the mid-1800s and who vastly outnumber them today. Those allowed to live in Bethlehem are confined to the matchbox houses and shacks of its black township or to the bleak huts of its white-owned farms. Thirty miles away, hundreds of thousands of others are confined to Qwaqwa, one of the most squalid and overcrowded of South Africa's black "homelands" slated for nominal independence.

History imprinted these lessons on the Afrikaner soul: to survive they must stay united and vigilant and keep their enemies divided; power and privilege are not divisible -- what another group gains, you lose.

"The past has a great hold over us," says Cehill Pienaar, a local farmer who ran as the Conservative Party's parliamentary candidate and who can trace his blood lines to French Huguenots who came to Cape Town in the 1680s. He still has a bloodstained family Bible with a gash in its pages from an African spear.

"My people fled France for their religious beliefs. They left the Cape for their political beliefs. And I'm making a stand here for both."

For years the political vehicle for Afrikaner aspirations was the National Party, whose leaders preached a straightforward gospel of white supremacy and Afrikaner unity. Bethlehem's parliamentary seat is one of only six in South Africa that has belonged to the Nationalists since 1914, the year after the party was formed.

After they came to power in 1948, the Nationalists constructed the airtight system of racial domination called apartheid. But 37 years of rule have dulled the Nationalist edge and brought forth a generation of leaders who speak a blurry language of racial accommodation and black rights, even if in practice they move at a glacial pace.

Their tentative moves toward political change have triggered a reaction on the Afrikaner right that has split Bethlehem and other small communities. The reaction started with the small Herstigte or "Reconstituted" National Party that broke off in 1969 and that won its first parliamentary seat ever in an upset last week. But it came of age with the founding of the Conservative Party three years ago.

To an outsider the ideological differences between Conservatives and Nationalists appear minor. Both agree that the white man brought the fruits of civilization to South Africa; that there is no black majority here, despite the fact that blacks constitute 73 percent of the population, but rather a series of 10 disparate African nations that would wage savage wars against each other were whites not in control; that black unrest is more the work of outside agitators and communists than a genuine revolt of aspirations.

But the Conservatives part company with the government in seeing political disaster in even the most hesitant gestures toward reform. "They think you can throw a couple of crumbs from the table and still be boss," said Pienaar. "We say it's dishonest and it'll never work. It can only lead to revolution."

The Conservative solution is to return to the fundamentals of apartheid: compel blacks to reside in the homelands, allow them voting rights there but not in "white" South Africa and permit those who live in urban areas to do so only as alien migrants, not citizens.

Conservative leaders shroud their views in dispassionate tones. But behind the message lurk the deepest racial fears of an outnumbered people who are afraid that once in power blacks might do to them what they have done to blacks.

Wessel Wolmarans, a slim, weathered cattle breeder, was one of the first to sign on with the Conservatives in 1982. He speaks two African languages and grew up among the black workers on his father's farm, but he sees most blacks as hopelessly inferior -- and those who are not as a threat.

"It's the educated ones who cause all the trouble," said Wolmarans, adding that his solution to the unrest would be the one the government used in the Sharpeville Massacre of 1960 -- shoot a large group of rioters.

The men who lead the Conservatives tend to shake their heads at Wolmarans' blatant racism. But their speeches and programs speak directly to his fears.

"If you yield to liberalism, integration and multiracialism, you'll commit suicide," Conservative Party leader Andries Treurnicht told a rally here last week. "If you adapt to sharing power with the blacks, you betray your own freedom and the future of your children and your grandchildren."

Treurnicht, who sported a red carnation in his lapel and an air of calm certainty, was once a Nationalist Cabinet minister. A former preacher who knows how to capture and hold his audience, Treurnicht portrays the ruling party and its leader, President Pieter W. Botha, as a movement that has betrayed a sacred trust.

"The National Party has deserted its people," he said. "Its policy is integration by stealth."

Treurnicht says he is convinced that Afrikanerdom can survive, provided that it returns to its apartheid principles. Others are less sure.

Dutch Reformed minister Brits, who sat on stage with Treurnicht last week, said he shares many of Treuernicht's fears of blacks and disdain for the Nationalists. Brits can trace his family's arrival in South Africa back to the 17th century, and one of his ancestors was a founder of Bloemfontein, the Orange Free State capital. But he speaks as if that long history is about to come to an end.

"We are such a small minority on this continent," he said. "We're a dying race. I am afraid we're going to disappear."

Brits admits that there is no going back to the days of undiluted white domination. He even concedes that the cruelties the white government inflicted in the name of apartheid are at least partly to blame for the crisis South Africa now faces. But, he said, when he contemplates a future of black rule, he feels only despair.

"We live in such different worlds, and we have almost nothing in common," he said. "Even their Christianity is very different from ours."

Brits is not alone in seeing the future in apocalyptic terms. Wolmarans said he would sell out and move his family, including three married children and nine grandchildren, to the United States, where he has visited, if South Africa's currency, the rand, were not so weak.

Even Pienaar, an unflappable candidate, said if the Conservatives do not capture Parliament in the next general election four years from now, "it will be too late -- we will all go down the drain." He believes many Afrikaners are prepared to fight to avoid that prospect.

At first the Nationalists tended to write off the Conservatives as a small lunatic fringe. But that has changed as they have watched the party grow. There is fear that the right wing will capitalize on white economic woes. Treurnicht increasingly is sounding a populist call, attacking both government and big business and bemoaning reports of hunger among poor whites.

Bethlehem's white farmers have suffered four years of anemic rainfall and growing debt, according to Pieter Luttig, general manager of the regional farmers' cooperative, although so far none has gone under.

Nonetheless, the Nationalists took the Conservative threat very seriously. When Botha came here to campaign, he spoke in tough tones and even held out the prospect of a cutoff of South African chromium to the United States should it enact tougher economic sanctions against his government.

Pienaar said his Nationalist opponent, potato farmer Paul Farrell, often sounded more conservative than he did.

"We South Africans, we're all conservatives," replied Farrell. "But the point is, we're also realists."