ELECTIONS : Religious Right Tests Clout in Minnesota : Incumbent GOP governor tries to pin extremist label on his conservative rival in primary.

MINNEAPOLIS —  Ordinarily a genteel affair, this year’s Republican gubernatorial primary has become a grueling test of the religious right’s political appeal beyond its traditional Bible Belt strongholds.

The role of religion in Minnesota politics is the dominant theme of today’s vote between incumbent Gov. Arne Carlson, a fiscal conservative with a moderate streak on social issues, and Allen Quist, a former state legislator whose candidacy grew out of a protest movement among the party’s deeply entrenched conservatives.

Surprised last spring when Quist captured the state Independent Republican Party’s endorsement, Carlson has spent much of his primary war chest of $900,000 in recent weeks, saturating local television with ads portraying Quist as a religious extremist. Carlson has compared Quist to Adolf Hitler, and aides have likened his followers to cult members.

Quist concedes that Carlson has had “some success” in cementing that image. And the ease of that effort comes as a warning to religious conservatives of the damage that can be inflicted on statewide candidates with overt ties to the spiritual right.

“What we’re learning is that we may have to find candidates who can’t be so easily labeled,” said the Rev. George A. Cable, a conservative Baptist minister and Republican Party leader who is one of Quist’s most ardent supporters.

Recent polls indicate that Carlson leads Quist more than 2 to 1 among Republican voters.

And while even some Quist backers are privately expecting the worst, political observers say Carlson’s ability to turn out his supporters is uncertain. They add that Quist could be aided by conservative Democrats allowed to cross over during the open primary.

Stark differences between Quist and Carlson extend from their beliefs to their images. While Quist blames the governor for allowing Minnesota to come under attack from forces of moral decay, Carlson stresses his own four-year term as a financial manager, vetoing Democratic spending measures and bringing the state budget under control.

Quist, 49, a compact farmer with calloused hands, is the physical antithesis of Carlson, 59, a tall, silver-haired eminence in sack suits.

Carlson’s private life has largely escaped scrutiny--except for the time that his ex-wife, Barbara, a Minneapolis radio talk show host, gave listeners details of their sex life.

Quist has not been as lucky. Within weeks of winning the endorsement of 69% of Republican convention delegates in June, he backpedaled as reporters and Carlson operatives began to mine his political career and private life for odd signposts.

Quist revealed that when his first wife, then six months pregnant, was killed in a tragic 1986 car accident, he buried her with the fetus enclosed in her arms “to express our family’s grief.” Former legislative colleagues described his “obsession” in floor speeches with curtailing pornography. In an interview, he insisted that men had a “genetic predisposition” to rule their families.

Despite trying to broaden his attack on Carlson by calling for a tax repeal, Quist repeatedly has returned on issues of morality, vilifying the governor for being too liberal.

In radio ads last week, Quist supporters claimed Carlson favored homosexual marriages and abortions in a woman’s ninth month of pregnancy.

The suggestions so enraged Carlson that he filed suit Thursday against Quist for violating campaign laws.

“On the face of it, it’s a foolish strategy,” Steven Schier, professor of political science at Carleton College in Northfield, said of Quist’s emphasis on moral issues. “You would think he would want to consolidate and broaden his base, not alienate it.”

Conservatives need a broad cross-section of Republicans, Schier and other political analysts say, because Minnesota’s religious conservatives are too few in number to provide a dependable base in statewide elections.

The stronghold of Minnesota’s religious right is in the state’s remote suburbs and in rural areas, where young couples “just starting out . . . are worried about the kind of moral decay they see around them,” said Darrell McKigney, the head of Minnesota Family Council, a conservative action group.

At Baptist minister Cable’s Chisago Lake Baptist Church in Chisago City, an hour north of Minneapolis, classrooms are filled with young children learning ancient biblical verities.

Cable tries to keep his Sunday sermons free of political talk, but admitted he could not help castigate Carlson after he signed a gay rights measure.

“We are people who think our governor should be behind family values,” Cable said. “Instead, we have someone who out-liberals some of our Democratic politicians.”

The battle on the Republican side has overshadowed the Democratic primary. None of the three Democratic-Farmer-Labor Party contestants--former police chief Tony Bouza, state Sen. John Marty and former state Democratic Party official Mike Hatch--has generated much heat.