Life in this 99 percent white Mississippi River town used to center around church, home, job and sports -- the stuff of Middle America.

But it lost its Middle American caste last August, when 750 members of Local 6 of the American Federation of Grain Millers struck the town's largest employer, Clinton Corn Processing Co.

Women, some minorities and kin of the strikers have been brought in as "replacement workers" in an attempt to break the strike by the nearly all-male and all-white union.

But over the weenend, some union supporters went the company one better -- they brought in black political activitist Angela Davis, who is also the vice presidential candidate for the Communist Party USA.

The Davis visit seems to have worsened an already tense situation in which families have been torn apart, chuch congregations have been split and even the union has been at war with itself.

Davis was invited to speak by Tim Yeager, a local lawyer and political activist. She was supposed to have spoken Saturday at the Local 6 union hall in Clinton. But union members, some outraged by the idea and others bowing to intense community pressure, voted against it.

Unpreturbed, Davis accepted an invitation to speak in support of the union and against union-busing at St. Mark's United Methodist Church in nearby Camanche. That invitation was made by the Rev. Gil Dawes, who is now being denounced by some members of his congregation as "a communist pig."

"It's tearing my church apart," Dawes said about the strike and the Davis appearance.

"It's tearing everything apart. We have sons and daughters crossing picket lines maintained by their fathers. We have brothers going in the plant while their other brothers are trying to keep them out -- they are using women and some blacks to work in the plant . . . What we have here is civil war," Dawes added.

It is a shared feeling in this stagnant industrial town of 35,000. Indeed, it is one of two things on which people here seem to agree.

The other is that the strike long ago moved from a fight over wages and working conditions to one involving the survival of Local 6 specifically and the future of unionism generally.

The conflict in Clinton is part of a larger war in which organized labor is trying to defend against what it sees as increasing attempts by businesses to break unions in the heavily organized Show Belt, and to prevent the spread of unionism in the poorly organized Sun Belt.

"That's the most important issue in this whole thing," said Michael Krajnovich, business representative for Local 6, who accompanied Angela Davis to St. Mark's Church.

"The issue is, do we have a right to maintain a union in a plant where we've been since 1937, or do we get busted? . . . What we're seeing here in Clinton is a deliberate attempt to break this union," Krajnovich said.

His fear is fed by the realization that several major unions have been decertified at Iowa companies the last three years.

Most of the decertifications came after lengthy strikes, precipitated by disputes over grievance procedures and working conditions. One occurred last year in Des Moines, where a United Auto Workers local was voted out of the Delavan Corp., a plunbing accessories manufacturing firm, after a 19-month strike.

The decertification was authorized by replacement workers brought in to the plant during the strike. Nearly all of the firm's 225 union members lost their jobs.

Officials of Clinton Corn Processing Co., a major division of Standard Brands, deny they are trying to accomplish the same thing.

Denials also came from Brenda J. Blanchard, executive director of the Greater Clinton Chamber of Commerce, which claims neutrality in the strike.

However Blanchard said she believes "there is a strong feeling in the local business community that the strike pesents a chance to strike a blow for free enterprise."

She also said she believes local businesses "care very much about providing the kind of work environment that, perhaps, can supersede the need for a union."

Davis, who was greeted by signs that read "Communist Go Home" and "Our Hockey Team Beat Your Hockey Team" as she entered the church, attacked Blanchard's sentiments.

"The union must remain to protect the interests of the workers," she told an audience of about 50 that included about a dozen reporters and about six members of Local 6.

Davis said minorities and women who are being brought to the plant to break the strike were "working against their own best interests." However, she said, "the bosses will always have the opportunity" to use minorities and women as strikebreakers "as long as racism and sexism exist."

"I certainly would not have come to the Clinton area if I thought that being here would hurt Local 6 and further divide the community," Davis said.

But the immediate signs are that her visit has done just that. Three officers of Local 6 have resigned, increasing to 100 or so the number of members who have left -- many to return to work at Clinton Corn -- since the strike began.

The Rev. Dawes, already under fire for his supportive role in the strike, has come under increased pressure to leave the post he has held for nine years.

"I don't understand it," said Krajnovich of Local 6. "I could have said exactly the same thing she said and gotten a standing ovation in our union hall. I guess it all depends on who says it."

Asked if he thought the strike would fail, especially in light of the furor created by Davis' visit, Krajnovich said:

"When you take a strike this far, nobody really wins or loses a damn thing. We've been out too long to gain anything financially. Now, it's simply a matter of trying to preserve dignity and of trying to keep our union." s CAPTION: Picture, 1, Angela Davis . . . "The union must remain . . ."; Picture 2, Camanche woman holding picture of Navy son protests Davis' visit to town.; Copyright (c) 1980, Des Moines Register