Republican Party strategists here have been quietly conducting a year-long drive to maintain peace between the bankers and the Baptists.

In South Carolina and the rest of the South, Christian fundamentalists have brought new vitality to the Republican Party, expanding the core of GOP loyalists beyond the country clubs into the textile factories and tobacco fields.

At the same time, however, the tenuous Republican alliance between old-line Republicans and fundamentalist Christians -- groups with almost no cultural or social common ground -- threatened to explode into potentially debilitating party bloodlettings twice this year.

In one case, party leaders in South Carolina quietly negotiated a compromise to head off a fight between the groups over the chairmanship of the state party. Such a fight, they feared, could threaten the gubernatorial chances of Rep. Carroll A. Campbell Jr. Meanwhile, Rep. Thomas F. Hartnett (R-S.C.), who has strong ties to the Christian wing of the GOP, has agreed to abandon his bid to run in the primary against Campbell, and to run for lieutenant governor instead.

But here in South Carolina's 4th Congressional District, GOP leaders have been less successful at peacemaking. They have been unable to surpress a contest pitting a country club businessman front-runner, Bill Workman, the mayor of Greenville, against an array of Christian and conservative-based candidates seeking the GOP nomination to the House seat now held by Campbell.

Jack Buttram, a former aide to Sen. Strom Thurmond (R-S.C.) now active in the Greenville Fundamentalist Forum, gives a hint of the fundamentalist impact on campaign issues in this congressional race when he explains his opposition to one of the candidates, state Rep. Rick Rigdon, who is backed by some other fundamentalist groups. "I told [him] I couldn't support him anymore. It's not political, but I really began to doubt his judgment. He's involved now with a radio station in Greenville that plays 'contemporary Christian' music, and it's not a good influence on our youth," Buttram said.

Despite its internal squabbling over issues like Christian rock music, no other group has provided as much new blood to the Republican Party, which is struggling to achieve majority status, as those who describe themselves as fundamentalist Christians. From 1976 to 1984, a total of 8 million white fundamentalist Christians, most of them in the South, changed their presidential votes from Democrat to Republican, according to surveys by The New York Times, Gallup and other organizations.

This swing not only strengthened President Reagan's 1984 landslide, but also provided key margins in the victories of Sen. Jesse Helms (R-N.C.) and seven Republicans who defeated Democratic members of the House in North Carolina and Texas.

In one of the clearest demonstrations of the realignment of the fundamentalist community, James L. Guth of Furman University, which is here in Greenville, surveyed 460 Southern Baptist clergymen in 1980 and 861 in 1984. In 1980, this key group of southern opinion leaders was largely Democratic, by 41 percent to 29 percent. Four years later, the survey found that the overwhelming majority identified themselves as Republican, 66 percent to 25 percent.

"There are approximately 40,000 Southern Baptist churches in the country; the denomination starts more churches each year than McDonald's opens hamburger restaurants," Guth wrote.

The infusion of fundamentalist Christians into the Republican Party here has not only turned Christian rock into a campaign issue, but it has forced establishment Republicans to change their style of politicking.

For both Democrats and Republicans in the South, the political struggle has concentrated on the working- and middle-class white "populist" vote, and Christians represent a vital source of GOP support in this contest.

"Populists have always been liberal on economics. So long as the crucial issues were generally confined to economics -- as during the New Deal -- the liberal [i.e., Democrat] could expect to get most of the populist vote," Lee Atwater, a South Carolina-based GOP strategist, said.

"But," Atwater argues, "populists are conservative on most social issues. Thus, when Republicans are successful in getting certain social issues to the forefront, the populist vote is ours. The trick we must master is choosing those social issues that do not alienate the country clubbers since, again, we need their votes and the populists' to win in the South."

In most of the South, Republican leaders have been able to avoid full-scale conflicts between country clubbers and the Charismatics. Tennessee is an exception. There, the division has become an open wound.

During the 1984 race to succeed Majority Leader Howard H. Baker Jr. in the Senate, establishment Republicans sought to force Ed McAteer, founder of the Religious Roundtable, out of the GOP primary. They saw his candidacy as divisive, threatening the general election chances of their favored candidate, Victor Ashe. To get McAteer out of the race, the Republican power structure took the unusual step of persuading the Republican Senatorial Campaign Committee, which normally avoids choosing sides in a primary, to back Ashe.

The action angered McAteer, who ran as an independent in the general election, siphoning off more than 5 percent of the vote -- support that almost assuredly would otherwise have been Ashe's. That election was won by Democrat Albert Gore Jr., who garned 61 percent of the vote to Ashe's 34 percent. McAteer considered an independent bid for governor this year, but abandoned the idea.

Christian-backed political efforts are extending to attempts to run party organizations in some states. In Texas and South Carolina, reluctant state Republican Party chairmen have been persuaded to seek new terms in efforts to head off Christian-based takeovers of the state parties.

In Texas, George Strake, who decided to seek a new term, faces a challenge from Diana Denman, the vice chairman who has significant Christian backing, in a contest to be decided next month. In South Carolina, Dr. George Graham, the party chairman and an ally of the establishment wing of the party, sought a new term and won, but only after promising to give the chairmanship to the insurgents after this year's elections.

Democrats are attempting to capitalize on these internal GOP conflicts but it is unclear how successful they will be. One test will be in North Carolina, following the Senate GOP primary victory earlier this month of Rep. James T. Broyhill, a member of the old-guard, over David Funderburk, who had the backing of much of the new-right Christian community. The general election will determine whether fundamentalists will maintain their Republican enthusiasm when the party has rejected their candidate or will stay home, helping Democrat Terry Sanford.