Joe Hays, a blue-eyed farmer who lives just south of here, was watching television news this summer and said to himself:

"Hhhhmmm, that's pretty neat. Pope in the USA."

The farmer then set off a chain of events that Iowans say will affect this state of corn and black dirt forever.

The mayor here is proudly predicting a traffic jam that will stretch for 30 miles. "All the way to Newton," he says.

The businessman who owns the state's tallest building -- a modest 36 stories -- says the visit "has to be the biggest thing in the history of Iowa."

And an editor at the Des Moines Register says his newspaper is treating the afternoon affair "like the Second Coming."

For four hours on the afternoon of Oct. 4, Pope John Paul II plans to drop by here for a glimpse of America's heartland. Up to a million people, from as far away as California, are expected to be waiting in this city of 194,000 to catch their own glimpse of the Polish-born leader of the world's 700 million Catholics.

The bishop of Des Moines predicts the pope's visit will inspire young men to become priests and turn fallen-away church members into "good Catholics again." There is a pope press conference here nearly every day, an altar for the pope is being made from a century-old white oak corn crib and about 1,500 portable toilets have been summoned from around the Midwest.

The whole shebang, as Iowans say, began July 19 on Joe Hays' kitchen table.

Hays, 39, a devout Catholic who when he was a sophomore in high school attended mass 363 days in one year, sat down there and wrote a letter on plain white paper, begging the pope to come to Iowa.

Hays does not have a copy of the letter any more. "They tell me the pope has it. That's kind of neat. Think of what that thing is worth."

When Hays first wrote the letter, Bishop Maurice Dingman of Des Moines remembers he did not think the request was worth much.

"When the farmer handed it to me and said it was for the pope, I thought to myself, 'What do I do with this?' I didn't want to disappoint this farmer because he was so sincere," recalled Dingman. "Now I know he was more than sincere. He had a premonition."

According to the Vatican, the pope wanted a chance to look at rural America west of the Mississippi during his seven-day, six-city tour of the United States.Dingman said the farmer's letter prompted Vatican advance men to come to Des Moines and check out the facilities.

They were given a tour of this quintessential Midwestern state that ranks 25th in both population and size and produces 10 percent of the nation's food supply. They went to Living History Farms, a 600-acre monument to farming that offers a cow pasture in the shape of an amphitheater. They also visited St. Patrick's Church, a tiny parish located in the cornfields 16 miles southwest of Des Moines.

A local priest, who followed one of the advance men, Bishop Paul Marcinkus, to St. Patrick's, said the bishop was ecstatic at the sight of the little, barn-shaped church. "This is lovely. This is really great," the bishop reportedly said.

The Vatican announced that Pope John Paul would stop in Des Moines to say mass at Living History Farms and helicopter over to St. Patrick's for a few prayers and a chance to talk with the Irish-American farmers of the parish.

Word of the pope's visit, which had been rumored for weeks, was announced last month in the Des Moines Register with the banner headline: "Proud Iowa Awaits The Pope."

Iowa, for the most part, has been bursting with pride since the announcement.

"People have always said, 'Where's Iowa? and "Where's Des Moines?'" boasted Mayor Dick Olson. "Well, for the next 20 years Des Moines will be a point of pilgrimmage for people to come and say this is where the pope was."

George J. Nahas, a city councilman who is planning to run for mayor this fall, calls the planned visit of the pontiff "the most wonderful, most precious thing that could actually happen."

Twenty years ago, Des Moines had its other "biggest event in Iowa history." Nikita Khrushchev, then the 65-year-old leader of the Soviet Union, came to town to look at tractor factories, farms and eat hot dogs. Khrushehev drew 150,000 in four cities.

But Iowans say that Khrushchev was small potatoes compared to the pope.

"The pope beats Khrushchev all to pieces," said Norman Hansen, a retired mechanic who was working in the John Deere tractor factory here when the Soviet premier toured the plant.

"Khrushchev was a big man, but he wasn't the pope," said Hank Bradshaw, a travel writer who lives here. "The pope's the only guy I know who they'll block a freeway for out in this country."

Interstate 80-35, a four-lane highway that cuts horizontally across Iowa just north of here, will be closed on the afternoon of the pope's visit.

The visit of John Paul, however, has not received universal acclamation in this overwhelmingly Protestant state. Iowa's 528,000 Catholics make up only 18 percent of the state's population; the rest are mostly Methodists and Lutherans. By contrast, Maryland is more than half Catholic.

The non-Catholic majority here has pressured city and state officials into keeping offices open on the day of the pope's visit. The decision to close local schools on the day of the visit has been sharply criticized over local radio talk shows.

There also are echoes of the anti-Catholic sentiment that until recent years had been a powerful political force in Iowa.

"He [the pope] may be the Catholic's God, but he's not my God," said a 66-year-old retired rubber worker who asked that his name not be printed. "The pope's not going to see anything here but a crowd. You ask him about farm people after he leaves and he won't know a thing about 'em."

Jerry Pecinovsky, the assistant city manager in charge of the pope's visit, said there has been considerable discussion among Protestants over why the pope has created "a big to do."

Linda Ward, a Mormon housewife in West Des Moines, said last week: "If it were Christ that was coming, I could see all the excitement."

Yet, the anti-Catholic talk here has been all but drowned out by the clamor and tittering of this small-town city as it prepares for what one Catholic farm wife calls "the greatest event of several lifetimes."

Unlike officials in Washington, who have become accustomed to handling huge crowds on the Mall, officials in Des Moines say they have no benchmarks to measure how severe crowd and traffic problems may be.

While District of Columbia Deputy Police Chief Robert K. Klotz is worrying about not creating the atmosphere of an "armed camp" when the pope visits Washington on Oct. 6 and 7, officials here say they are worried that when the pope-watching masses drive away from Des Moines in the evening they could take off with all the city's October gasoline supply.

In all of Iowa's 56,290 square miles nowhere is the excitement and worry over the papal visit greater than at St. Patrick's Church, the 111-year-old wood-frame building that for 20 minutes will accommodate the pope.

The church, accessible by a gravel road that cuts through little valleys where the air is heavy with the smell of pigs, is the oldest parish in central Iowa. Its 204 parishiners are descendants of the Irish Catholics who in the mid-1800s fled the Irish potato famine and came West looking for good land.

Last week, after getting official confirmation that the pope would come to their church, the farm families of St. Patrick's were besieged by reporters who asked what it all "felt like" and by relatives who telephoned to say they would not mind visiting on Oct. 4.

The church council met last Tuesday night and decided that only church members wearing special badges will be admitted to the 240-seat sanctuary on the day the pope comes. The Secret Service plans then to cordon off the 40-acre church grounds.

In the meantime, church council president Gary Kiernan said the men of the church will guard it 24 hours a day to keep away souvenier hunters and vandals.

"These farmers can do without a little sleep. It'll get them in shape for the harvest," said Kiernan, who farms 700 acres of corn that he expects to harvest at about the same time the pope is scheduled to arrive.

Other church members have been dispatched to repaint the holy water font and mow the cemetery lawn, wherein are buried men and women from every county in Ireland.

Maurice Lynch, 65, who was born on the 700 acres he still farms, said it still puzzles him that the pope would come to Iowa and stop at St. Patrick's.

"I can't see him coming out here. There are so many large cities for him to go to. But I'm going to talk to him. I haven't come up with nothin' yet to say," said Lynch.

Pope John Paul will arrive by helicopter at St. Patrick's and land in a hayfield near the church. John and Marilyn Conner own the hayfield and among all the members of St. Patrick's, they appear the least agitated over the papal visit.

"You see, it was all just rumor to start with and being a farmer I don't get excited 'till I see the pope here," said John Connor, who is raising his five children on the 1,000 acres that his great-grandfather settled here in the late 1840s.

Marilyn Connor conducts tours of St. Patrick's nowadays and says it seems "funny" that she and her family have to worry about security and access passes on a farm that "before the pope" wasn't even guarded with a wire fence.

"You know," she says, "when I think about the pope in our little church, I'm pretty amazed."