Steve Forbes's campaign bus rolled to a stop here one recent morning, its loudspeakers blaring "Stars and Stripes Forever." Young aides quickly erected a flag-framed photo set on the town square and pointed a digital camera toward the old courthouse. The crowd lined up, and the candidate moved into position. Show time.

A generation ago, small circus companies plied the little towns of the Midwest. Their trucks or wagons would arrive overnight, and in the morning, in a local park, they would erect the Big Top, put their wild animals on display and crank up the calliope for the evening performance. They were gone as quickly as they arrived -- but they were often the highlight of the long hot summer.

The circuses of old are gone but, in Iowa this summer, they have been replaced by the caravans of presidential candidates following the long, straight highways from county to county, hoping to spark a chord that will launch a movement that will carry them to the White House.

On Aug. 14, Iowa Republicans will conduct their quadrennial straw poll in Ames, an event that should have no particular meaning in the way America elects its presidents. But the candidates and their handlers are treating it almost as if it were the February caucuses themselves.

"Don't wait until February to come out and vote," Elizabeth Dole tells people, "because this is going to be important." Patrick J. Buchanan, as always, speaks in the starkest of metaphors: "The grim reaper is going to be waiting outside the gates of the Ames field house."

And so the state is awash in contenders, who arrive, set up, entertain, pack up and vanish like the circuses of old -- not in a day, but in 90 minutes or less. By the time the roadshows arrive in Ames next month, Lamar Alexander will have visited 60 counties. Gary L. Bauer is in the midst of a 21-city, 1,100-mile buscapade. Forbes will spend more than 20 days over a six-week period campaigning here.

Texas Gov. George W. Bush, in this as in so much in the Republican fight this year, is an exception. He will have spent only seven days in Iowa this year before the spectacle in Ames.

The candidates flip pancakes, appear at ice cream socials, play host at barbecues and practically beg the local newspapers and radio stations for attention. Sometimes their crowds are impressive -- 100, 200 or more. Sometimes they're plain discouraging -- a dozen or less.

The lengths to which the candidates go to court the citizens of Iowa are humbling -- no, humiliating. "They're making fun of the way I eat," Bush joked as he dipped a hamburger into some ketchup at the 2nd Street Emporium in Webster City the other day. Without missing a beat, a man standing nearby responded, "As long as you don't have your foot in your mouth, you're okay."

The television cameras remained fixed on Bush as he tried to chomp down his burger and fries. "How long are you all going to observe me eating?" he finally complained, and his aides quickly gave the signal to the camera people to shut down their lights.

To draw a crowd, candidates with money erect flashy stages with bunting and big American flags and canned music. Some lure voters with free breakfasts or free lunches. The deep-pocketed Forbes offers commemorative lapel pins for those who agree to recruit others to come to the straw poll. "This is the collector item of 1999," Iowa coordinator Steve Grubbs says enthusiastically, claiming the pins will supplant Beanie Babies. Look for them soon on eBay.

But Forbes has a slicker, high-tech bauble to offer his audiences: instant photos. At the beginning of his events, Forbes poses with anyone in the crowd. Then, as he gives his speech, his aides take the digital camera to the back of one of his buses, where they process the photos on laptop computers and print them on high-speed printers. Before Forbes departs for his next appearance, the campaign distributes the photos.

The campaign caravans roll through the lush Iowa countryside, past big grain elevators and water towers and Dairy Queens and root beer stands, past emerald fields of corn and soybeans that disguise -- or perhaps accentuate -- a growing farm crisis brought about by bumper crops, shrinking markets and rock-bottom prices. It is a crisis that has made the flock of GOP candidates question their devotion to free market principles.

The other beauty of Iowa is the directness of the voters. When Dole campaigned in Winterset, a young Navy officer asked whether she had the stuff to be commander in chief. When Forbes arrived in Jefferson, one man stopped him before he had barely gotten off the bus. "You're not getting your money's worth from your ads," he said. In Des Moines, a voter yelled at Bush to quit flipping pancakes for the cameras so that hungry people could eat.

The candidates compete with one another to appear folksy, lapsing into what they assume to be rural vernacular. Dole complained about those "derned" estate taxes that sometimes force heirs to sell off family farms to pay inheritance taxes. Every Republican wants to get rid of these "death taxes," as they like to say. Bush got carried away at one stop, promising to eliminate "death penalty taxes."

The endless days of campaigning cause candidates to do and say odd things. "Well, here we are in Ames," Bush said. "I've heard of it." Dole launched into a digression about gauze. "For 3,000 years we've had gauze," she said. "Plain old gauze." No wonder that by the end of her fifth town meeting of the day, Dole wistfully told her traveling companions, "I would like a good steak and a glass of red wine."

The biggest crowd Alexander saw last week had nothing to do with politics. It was drawn by the television program "Antiques Roadshow," which was taping in Des Moines last Saturday. Alexander looked longingly at the line of people that stretched for blocks waiting to get in. Then he quipped, "I'm afraid Forbes will find them and rent them for the 14th."