COUNCIL BLUFFS, IOWA, FEB. 7 -- The politicians may call Pat Robertson's backers the "invisible army," but Pam Barrett has been an intensely visible political force around Pottawattamie County this winter, personally contacting all 553 registered Republicans in her precinct and supervising the Robertson forces in 29 other precincts here on the high banks above the Missouri River.

Still, when precinct captain Barrett leads her troops into the Edison School gym Monday night, it will be the first time she has ever set foot in a precinct caucus. "I always thought other people did politics," she said. "I never knew the caucuses were for me."

All over Iowa, thousands of people who never "did" politics before are preparing to vote for Pat Robertson in the Republican presidential caucuses. Over the past week or so, this "invisible army," recruited largely among blue-collar fundamentalist Christians who yearn for moral leadership, has become increasingly visible.

Robertson, consequently, is poised to fight it out at the finish with front-runner Sen. Robert J. Dole and Vice President Bush. "What I'm seeing," Robertson said to large crowds of fervent supporters this weekend, "is that something big is happening for us in Iowa."

If enthusiasm, organization and a dedication that borders on outright devotion mean anything, he may be right. The Des Moines Register's final poll, published in Sunday's editions, showed Robertson running third at 13 percent behind Dole (37 percent) and Bush (23 percent) among Iowans who said they were likely to attend the caucuses. But among those who said they were certain to attend, Robertson leaped into a virtual tie with Bush for second, with 19 percent to the vice president's 20 percent; 35 percent were for Dole.

For all the new faces in its ranks, Robertson's "army" has a traditional pyramid-style structure, with statewide leaders who are political veterans guiding eager, energetic teams of district, county, town and precinct organizers. It is the same kind of structure that won key caucus victories for Robertson in Michigan and Hawaii.

At the ground level, the Robertson supporters tend to be neophytes like Pam Barrett. When the campaign held a training session last week for 100-plus precinct workers, about 70 percent said they had never been to a caucus before.

Robertson said he is pulling many Democrats into his crusade, and that seems to be accurate. When The Washington Post contacted four dozen Iowans who have recently changed their registration from Democratic to Republican, half said they did so just to vote for Robertson. And more such voters may turn up at Republican caucuses Monday night, because under the rules here, people may take part in a GOP caucus even if they are not registered Republicans.

For the most part, the Robertson recruits have been drawn to the long-time religious broadcaster by two forces -- the ancient pull of religious conviction and the modern magnet of television.

Not everybody voting for Pat Robertson is a born-again or fundamentalist Christian -- Nancy Davis, a Robertson leader in Dubuque, is the wife of a "mainstream" Methodist minister -- but a large majority of his backers seem to be.

Ernie Ratcliff, a 40-year-old salesman who is Robertson's Clinton County chairman, is typical. He resisted at first when a local pastor asked him to work for Robertson. But then, he recalls, "the Lord was urging me, 'This is something you should do.' "

"So my wife and I prayed," he continued. "My daughters prayed with us." In the end, he heard a calling to work hard for Robertson. "Pat Robertson is a born-again Christian," he explained. "That is basic. You build from that."

"When you look at the problems of the country, most of them get back to going away from God," said Larry Eugene Nevenhoven, a car salesman from Fort Dodge. He said the pastor at his church, Faith Assembly, has urged all parishioners to "go for Pat."

Robertson plays down his evangelical roots, fearful that his religious ideas will scare off nonfundamentalists. He bought a two-page ad in Sunday's Register complaining that he faces "the same kind of prejudice" that greeted John F. Kennedy in 1960.

The candidate has crafted a stump speech in which he communicates clearly his born-again faith in language that is not threatening to others.

Robertson relates, for example, a moment months ago when he found himself saying that he will definitely become president if he can win in Iowa. "It just came up inside of me, and I said it," he declares. "And as soon as it came out of my mouth, I knew it was truth." To many of his followers, that wording suggests that Robertson is repeating a message that came from God.

Robertson's 30 years as host of a television ministry is an enormous boon for him in an era when the TV screen provides national celebrity and stature. Robertson's TV ministry, Christian Broadcasting Network (CBN), said that more than 70,000 Iowans have contributed to its work over the years. Interviews indicate that a large proportion of his political base has prayed with him electronically for years.

"This nation needs, and this world needs, somebody who can be a witness in the spirit, okay?" said Devy Wilbur, a friendly mother of six from Fulton. "And I've seen Pat witness to the spirit of God on television. Not every man can do that, okay? Not anybody else in this election can."

Wilbur said her father was healed after an electrical accident because of prayers Robertson offered on his TV show. Last month she drove back and forth across northern Iowa, stopping in each town to say a prayer for Robertson's success.

Morris and Marion Axne of Fort Dodge, who switched their registration to Republican last month to vote for Robertson, are among many Iowa backers the candidate found because of his ministry.

"We haven't really gone to any meetings or anything," said Morris Axne. "But a lady came to the door, and said aren't we CBN contributors. She gave us the card to register Republican and told us where the caucus is. It's on the 8th, I guess. At North Junior High."

Robertson has been drawing larger and larger crowds in recent days, and his supporters respond with ear-splitting enthusiasm to his exhortations. And when the candidate winds up with his greatest applause line -- "Give me the chance to see the look on Dan Rather's face when he has to say, 'Pat Robertson won Iowa' " -- the crowd comes roaring to its feet.