In six weeks, voters from across Iowa will gather in this sleepy town to gorge on barbecue catered by Mustard's or Hickory Hill and listen to the country-and-western sounds of Crystal Gayle, Tracy Byrd and Linda Davis, all for free, including the $25 ticket.

With transportation provided from the farthest reaches of the state, some 10,000-plus people will get a chance to shake the hands of Arnold Schwarzenegger, H. Norman Schwarzkopf and maybe even former British prime minister Margaret Thatcher. As a special added attraction, they can get their pictures taken with Miss Iowa, Jaclyn Solinger.

All this hoopla costing well over $3 million will be paid for by Republican presidential candidates seeking support in a technically meaningless straw poll here Aug. 14. But what was once an insignificant event has become a make-or-break episode, with the potential of ending the aspirations of a half dozen candidates.

Traditionally, the Ames poll was a way of getting activists from around the state to gather to build enthusiasm for the election-year nominating caucuses as well as to raise money for the state GOP from the $25 attendance fee. As candidates made their pitches for support, participants would cast ballots giving an early signal of organizational strength.

Now, with Texas Gov. George W. Bush dominating the chase for campaign contributions, the straw poll has suddenly become a test of viability for the other candidates -- if they cannot make a good showing here, it will be very tough to survive, financially and politically.

"Bush has the potential to terminate the nomination process effective August 14," said Brian Kennedy, national political director for Lamar Alexander's presidential campaign. "What he would like to do is short-circuit all the caucuses and primaries that fall next year by having a big score on August 14."

In a reflection of how important the Ames straw poll has become, Bush just outbid rival Steve Forbes, paying the Iowa Republican Party $43,500 to rent for one day 60,000 square feet of grass outside the coliseum where the straw poll will take place. That piece of land is the best spot for barbecues and bands and to otherwise influence Iowans before they vote for their choice for president.

"We are in it with both feet," declared Bush spokesman David Beckwith.

Bush raised the stakes last month when he said he would not duck the contest, as some thought he might, and that he intended to win. His Iowa manager, Luke Roth, escalated another notch, saying his goal was to get 5,000 supporters to show up -- double the record of any previous candidate.

"He really laid down the gauntlet," said Bob Haus, Forbes's Iowa manager. "Bush has chosen to fight on turf that others have been on for quite some time. A lot of campaigns feel like he just started a fight in their home town."

When it comes to the Ames Straw Poll, Haus is no slouch. Four years ago, he managed the presidential campaign of Sen. Phil Gramm (R-Tex.). Gramm spent more than $800,000 on the event and tied Robert J. Dole, with 2,582 votes each. "Gramm changed the paradigm," Haus said with a smile. This year, Forbes is the only candidate, because of his personal wealth, who is able to go head to head, dollar for dollar, against Bush, who broke all records raising $36.25 million in the first six months of the year.

Haus, like those in other campaigns, is holding spending plans close to the vest. He said Forbes operates on principles of Scottish frugality, but "there are always unanticipated expenses going down into the stretch."

Haus declined to identify the entertainers and celebrities the campaign is trying to book, but he did not rule out Thatcher, and, he declared, not only would the music equal Bush's, but there would be something for everyone, including Christian pop for the religious conservatives Forbes is trying to attract.

While Bush has taken a high-risk gamble by escalating the importance of the straw poll, he does not have as much to lose as most of his competitors. "With the money he's got, he can risk $1 million or so on Ames," a GOP strategist said. "If it doesn't pay off, he's got plenty for the next go-round. For everyone else [but Forbes], even half that amount is a killing expenditure, and if they lose, their money supply is going to dry up."

Bush's campaign is fully aware of the liabilities of the straw poll for competitors and sees the opportunity for the early kill. "It is entirely possible that with the emphasis that is being placed on the straw poll that somebody afterwards could say, `We don't have the money to go on,' " said Bush spokesman Eric Woolson.

The candidate with the most at stake is Alexander, whose cash flow has slowed to a trickle and who has said his candidacy's survival depends on doing well here. But Elizabeth Dole and former vice president Dan Quayle also must have respectable showings to be competitive in next year's primary contests.

For the very conservative candidates -- Gary L. Bauer, Patrick J. Buchanan, Sen. Robert C. Smith (N.H.) and Alan Keyes -- the Ames straw poll is likely to determine who can make the strongest claim to carry the mantle of the right, the role Buchanan assumed four years ago. The consensus here this time is that that may be Bauer. He has lined up the backing of most of the state's conservative leaders, and his campaign is being run by Marlys Popma, a widely respected grass-roots organizer.

The straw poll is an ideal vehicle for candidates appealing to the ideologically committed. "I'm obedient to what it is I believe the Lord told me to do," Popma said. "I'm hoping and I'm praying that the end of the line is a Gary Bauer presidency. But if that is not what God's end line is in calling me to do this, then that will become clear as time goes on."

Her views are a contrast to those of the more pragmatic Roth, Bush's man here. "Winning is very important," the former collegiate defensive tackle said. "I like to win. . . . I was a conservative at Princeton in the mid-'70s. I had to defend Nixon during Watergate. I had to be tough or die."

With so much riding on the outcome of the straw poll, the incentive to cheat is enormous. There is no penalty if someone gets caught for voting more than once, because there is no state or federal law governing the rules. Four years ago, people were seen voting, then washing the entry stamp off their arms and voting again. Republican consultant Mike Murphy admitted he voted repeatedly in an attempt to publicly downgrade the importance of the event. This year will be different, Republicans here say, pointing to Kayne Robinson, former deputy police chief in Des Moines and the new GOP chairman. Capitalizing on his years on the force, Robinson is devising secret security measures to end multiple voting.

In the meantime, the candidates this week began to pull out the stops, arriving in Iowa in droves in bids to attract credible levels of support at the straw poll.

"A lot is at stake for a lot of us," Alexander said yesterday as he began what will total 23 days in the state between now and Aug. 14. "I plan on making a stellar showing. My reason for going to 60 counties is to improve my chances of making a good showing."