In the suburbs of Minneapolis, Sharon Mueller, a woman once shunned by the GOP establishment, has emerged as a driving force in a conservative-evangelical Christian takeover of the state Republican Party.

Just seven years ago, when Mueller went to her first Republican precinct caucus, almost no one would talk to her.

"I tried to volunteer for things, but I was never called," Mueller said. "What I didn't know was that there was kind of a shut-out policy which isn't quoted, it's just there. There was liberal and moderate control. They had their people involved, they had their people doing the work."

Today, Mueller is a leading grassroots organizer in a Christian vanguard that is changing the way the Republican Party conducts politics in states as diverse as Texas, North Carolina, Alaska, Georgia, Virginia and Oklahoma.

On a national scale, this movement is emerging as a force to be reckoned with in Republican presidential politics. Viewed in terms of power within a political party, and disregarding ideology, the muscle of the Christian right in the GOP is roughly parallel to the power of the AFL-CIO or the National Education Association within the Democratic Party.

In 1984, just over 20 percent of the delegates to the Democratic convention were members of the AFL-CI0 and about 12 percent were NEA members. Republican officials privately estimate that from 15 to 20 percent of the GOP delegates in 1988 will come out of the Christian movement.

The glue holding the Christian right together is its members' intense opposition to abortion, although other common goals include school prayer, the mandated teaching of "scientific creationism" and the elimination of both moral "relativism" and "man-centered secular humanism" from the political and educational processes.

In Minnesota, Republican political gatherings are now being held in places like The Jesus People Church in Minneapolis as well as wine and cheese parties at golf clubs; the Temple Baptist Church in St. Paul instead of a union hall. The arcane procedures of precinct caucuses are taught after the lessons of the scripture. This brand of conservativism took on and crushed Rep. Bill Frenzel (R-Minn.), the senior member of the state's congressional delegation, in a battle for control of the Third District's Republican Party machinery. In the March, 1984 Minnesota precinct caucuses, says Mueller, "we just won everything, including the state central committee in the Third (Congressional District), the Fifth, we're good in the Sixth and not quite solid in the Fourth."

Across the country, the strength of the Christian-Republican movement varies widely from state to state. In many southern and Rocky Mountain states, it is a significant force, lacking majority control but in a position to flex strong muscles through alliances with right to life, anti-ERA and other conservative factions.

In Virginia, for example, the Christian right now dominates the Republican Party in the area surrounding Norfolk and Virginia Beach, but remains a minority state- wide, unable to determine the nomination of favored candidates for governor or lieutenant governor. In the Texas GOP, officials estimate that a sixth of the state executive committee is made up of persons clearly identified as part of the Christian evangelical movement, as were a fourth to a third of the 5,000 delegates to the state convention last year.

Warren Tompkins, executive director of the South Carolina Republican Party, said, "Christians are a very integral part of our party. At a state convention, it's about 25 percent of the delegates. We've got two or three groups. We've got a group that's got leadership out of the Bob Jones University, and then the Pat Robertson group and somewhere along the line the (Moral Majority's Jerry) Falwell group is meshed in."

In Oregon, there is a continuing struggle for control of the state GOP between party regulars and Christian conservatives that dates back to 1964, when the nomination of Sen. Barry Goldwater (R-Ariz.) mobilized the Republican right throughout the West and South.

In Alaska, the Moral Majority, run locally by the Rev. Jerry Prevo, took over the GOP in 1980. Since then, party regulars have regained at least partial control, although the Moral Majority remains a major force. Republican sources there said that both the regulars and the Moral Majority have agreed to downplay the organization's role in the GOP because the Moral Majority has a highly negative image among many Alaska voters.

The emergence of the Christian movement in Minnesota is not a chance event resulting from a weak local Republican Party ripe for takeover by any group prepared to mobilize a few troops. This is a state with a long history of a strong state Republican Party, and the gains made by the Christian movement have been in battles with a sophisticated GOP establishment. The Christian- conservative coalition has not yet taken over the state-wide GOP leadership, but its power includes enough votes to run over the opposition at the state party convention on specific issues.

Allen Quist, a freshman Republican elected last year to the Minnesota House as part of a cresting wave of Christian political activity, said: "I don't know how to gauge it, but I can say this: At the last convention, the Christian right was able to do virtually anything it wanted to."

In recognition of the importance of the movement to the GOP -- not just in Minnesota but across the country -- the Republican National Committee has appointed a liaison officer, Doug Shaddix, specifically assigned to work with evangelicals, along with the right-to-life and conservative ideological movements. Similarly, in the last election, Joe Rodgers, finance chairman of the Reagan-Bush '84 Committee, organized a separate, private fund-raising program designed to channel over $1 million into the Christian movement, primarily for voter registration.

The movement has stunned Minnesota GOP stalwarts such as Frenzel and Sen. David F. Durenberger.

"In Minnesota and other parts of the country, we seem to be narrowing the structural base of the party," Durenberger said. "That is, the party organization itself is gradually being taken over by those who have strongly held views and little tolerance for people in political life who hold different views."

Durenberger says the Christian evangelical movement is becoming so strong nationally that he believes its members will determine the 1988 Republican presidential nominee.

"It means that the range of the 1988 convention will be narrow," he said. "And it means that you can almost predict that whoever gets their blessing is going to be the Republican candidate for president. It's not going to be (Vice President) George (Bush), (Senate Majority Leader) Bob (Dole) or (former Senate Majority Leader) Howard (Baker), some of those kind of centrist types. It's going to be somebody who can accommodate to their views on most of the issues."

Asked if Rep. Jack Kemp (R-N.Y.) fit this bill, Durenberger said: "Oh yes, you bet."

Sen. Dole, asked how strong he expects the Christian right to be at the 1988 GOP presidential convention, said cautiously: "It will be a factor." He said he "will know better after next year," referring to the fact that he faces reelection next year and has yet to decide whether to organize a serious drive for the presidency.

Two key GOP presidential strategists, who spoke off the record out of reluctance to challenge the movement, both argued that the Christian right movement will be a strong minority faction at the 1988 Republican presidential convention, but both contended that there are a number of forces working against the movement becoming the determining force in 1988.

They pointed out that Jerry Falwell of the Moral Majority has already endorsed the candidacy of George Bush, despite the belief held by a number of Republicans that Kemp has a stronger appeal than Bush among evangelicals. Both strategists were critical of the claims of power made by a number of leaders of the Christian movement, although both talked only on a background basis, choosing not to publicly challenge it.

A number of the Christian leaders are far more assertive in their assessments of their own power:

"The Republican Party cannot elect a presidential candidate without the evangelicals," said Ray Allen, a rural Granberry, Tex., pastor and president of Christian Voice, which issues moral "report cards" on members of Congress. "We are everywhere."

Perhaps most assertive is Gary Jarmin, executive director of the Christian Voice Moral Government Fund and chief lobbyist for Christian Voice, a hybrid political organization.

"There is a realignment occurring," he said. "There are very few states in the country where we can't make it happen. The way I look at it, no state is safe."

A backer of Kemp for president in 1988, Jarmin predicted the following scenario in the next competition for the GOP nomination:

"We swamp the caucuses in Iowa in 1988. You heard it here. We are going to swamp the caucuses in Iowa. Jack Kemp is going to get it. He is going to go to New Hampshire and win it, and by that time, it's all over."

Christian Voice, which played a central role in mobilizing over 1,000 Christian fundamentalists -- all political neophytes -- as delegates to the 1984 Texas State GOP convention, is making a conscious effort to expand the "Texas plan" to other states:

"What we want to do is take the Texas thing as our prototype, we want to take this nationwide," Jarmin said. "Where the Republican Party is weakest, in the South, we are strongest."

In a separate drive, Dr. M. G. "Pat" Robertson, founder and president of the Christian Broadcast Network (CBN), is setting up a national network of "Freedom Councils," which CBN officials describe as "nonpartisan." Robertson is also considering a run for president, according to CBN spokesman Earl Weirich. "He said a number of people had come to him and proposed this, that he consider it. And he said 'The best I can say right now is, "I'll consider it.'" Many politicians, both Republican and Democratic, have suggested that the growing involvement of evangelical, born- again Christians will become a liability to a Republican Party seeking to build strength among young people who are fiscal conservatives but more liberal on social issues.

In this view, the Christian right's opposition to abortion, increased sexual freedom and "secular humanism," along with its support of school prayer, will alienate many young voters who supported Reagan in 1984, but who do not want their own life styles suddenly regulated.

To date, however, the GOP's Christian mobilization has been a political gold mine.

Of the 15-seat Republican gain in the House in 1984, eight were in districts where conservative Christian activity was clearly an important part of the election, particularly in Texas, North Carolina and Georgia. The Christian mobilization was critical to the reelection of Sen. Jesse Helms (R-N.C.) and contributed substantially to the decisive victory of Sen. Phil Gramm (R- Tex.).

Most important of all, however, is the fact that the Christian mobilization is an expansion of the Reagan constituency that has translated directly into straight party-line voting for Republican candidates right down the ticket to lower-level offices.

In the once firmly Democratic terrain along the Route I-85 corridor from Greensboro to Winston-Salem in North Carolina, Republicans last year more than doubled their numbers in the state legislature from 18 to 37. In Texas, GOP state House strength grew from 37 to 53.

Another force behind the movement is the populist challenge by the lower-middle-class and middle-class whites to an elitist, affluent and privileged Republican establishment. "Traditionally, the Minnesota Republiccan Party has been a closed, small group of people who were primarily interested in fiscal conservativsm," said Frank Grace, the Minnesota GOP national committeeman. "It got to be very exclusive. The Reagan movement inspired these people who thought the country was going bad to come in."

Republicans in Minnesota made decisive gains at the bottom of the ticket, depite the fact that it is the one state in the union Reagan failed to carry. The GOP captured the Minnesota House as a 77-57 Democratic majority shifted to a 70-64 Republican majority, and a Republican Party once considered among the most liberal in the nation pushed through conservative legislation that included sharp welfare cuts, shifts in education aid from the cities to the suburbs and reductions in summer jobs.

In the process in Minnesota, Sharon Mueller has become what amounts to a Christian political boss, although she prefers to call herself a "motivator."

Knowing the 1984 precinct caucuses -- the grass-roots base of the Minnesota Republican Party -- would be held in late March, Mueller, working with the Greater Minneapolis Association of Evangelicals, "started in January. I did three months of caucus workshops, in schools, churches, homes."

Frenzel, recognizing that he was in danger of losing his own district party structure to conservative forces adamantly opposed to his pro- choice abortion stance, pulled out the stops to get his allies to the precinct caucuses. It was futile.

"At our convention," said Maybeth Christensen, Frenzel's district director, "there was a young man who stood in one of the aisles and had on one of those straw bowler hats.

"When he had his hat on, everybody would vote yes, when he took his hat off, everybody would vote no. It was an amazing thing to watch. The votes went exactly the way his hat went. We had less than 100 votes out of more than 300. They were in total control."

In this atmosphere, Frenzel did not attempt to become a delegate to the Republican National Convention in Dallas. "He said he had been twice and did not need to go again," Christensen said, with a laugh. But the Christian right knows it would lose if it challenged Frenzel in an open primary. This reflects its strengths and weaknesses elsewhere in the country.

The movement has been strongest in party battles where power comes from producing blocks of voters at precinct caucuses. Caucuses have little appeal to most voters, making them ideal targets for groups such as churches that can produce ready- made constituencies.

In a process very similar to that in Minnesota, the Christian right in Oregon has periodically taken over the state GOP but has been unable to oust such adversaries as Sen. Bob Packwood (R-Ore.). "They don't do all that well at the ballot box, but they do a hell of a job in the party organization," Jack Faust, a moderate Oregon Republican, said.

The growing strength of the Christian right within state Republican parties is, however, likely to translate into relatively strong delegate strength at the 1988 presidential convention since just under half of the convention delegates are slated to be selected through caucus systems, as opposed to open primaries.

The influx of Christians to the party has produced a different breed of politician. Take the case of Minnesota's John M. Hartinger, pastor of the Victory Baptist Church and a follower of the Moral Majority's Jerry Falwell. He first ran for the legislature in 1982 and lost.

After much agonizing -- "I had people coming to me after the election and saying, 'Johnny, your prayers don't mean a thing.'" -- Hartinger ran again in 1984.

"At 4 a.m., there were three precincts left, I was 124 votes behind. I said 'Lord, it's in Your hands. You've got to make up 124 votes.' There was a lot of boldness in my prayers. I went to sleep. At 6 a.m., my wife rapped me on the shooulder and said, 'You're ahead by 54 votes.'"