DES MOINES -- This is the hour of reckoning for Laura May, a 23-year-old whose entire career has thus far amounted to the precarious presidential campaign of Bruce Babbitt. "You run through all the scenarios in your mind, from imagining yourself planning the logistics of his inaugural to worrying about where you'll be working in a week," she said after a Babbitt breakfast last week. "I expect the next few days will be nothing short of an emotional roller coaster."

Hundreds of determined campaigners like May descended on this farm state more than a year ago, spending their days canvassing the flatlands in beat-up cars, sleeping in cheap motels, banging on farmhouse doors -- all to persuade just one more person to come out on caucus night.

By last month, their number had tripled.

As they plunge into the final hours of the longest precampaign period ever, as they continue to work 14-hour days surviving on Diet Coke and candy bars, fiercely insisting that the results of tonight's caucuses will make it all worthwhile, they are also faced with the scary realization that the dress rehearsal is over.

Before, they always had six more months, six more weeks, six more days. Today, they are operating on the ragged edge of potential disaster.

"There's still 15 percent out there who are undecided," says Teresa Vilmain, state coordinator for Massachusetts Gov. Michael Dukakis. "That's what I lose sleep over."

This is the land of true grass-roots politics, where a cup of coffee at the town diner with a few farmers can, at times, bear more fruit than running statewide television spots. Success depends on persuading supporters to brave the Iowa cold and attend an evening precinct meeting to declare in front of their neighbors which candidate they prefer. The political acumen of a hired gun may be important in this situation, but relentlessness is the name of the game.

Here is how the game is played in Iowa as seen by three very different field workers -- a highly paid professional from Washington working for George Bush, a native Iowan for Dukakis, a young college graduate who moved here two years ago for Bruce Babbitt -- and what the stakes are to each of them.

The Trouble-Shooter On the wall-size calendar in Rich Bond's stark office, Tuesday, Feb. 9 -- the day after the Big Event -- is highlighted. Sketched in the "9" box in pencil is a car, wheels in motion, smoke circling out of the exhaust. "That's me," says Bond, Bush's main man in Des Moines, "getting outta here!"

This is not where Bond, a $100,000-plus-a-year Bush operative and native New Yorker, was supposed to be spending his winter.

But when the vice president finished an embarrassing third (behind Pat Robertson and Bob Dole) in the Ames, Iowa, straw poll last September, the Bush family knew exactly what had to be done. Within 24 hours, they had dispatched Bond to Iowa. He has been this way before.

In 1980 it was Bond who was credited with orchestrating Bush's upset Iowa victory over Ronald Reagan. And so today, Bond appreciates that losing Iowa needn't be the end of the world. "We're playing to win, but I don't know if we can," Bond said during a late-night interview last week. (Lowering expectations is also part of his job description.)

In the past six weeks, the race here has turned into a brawl between Bush and Dole, with Bond and his army struggling to close Dole's lead in the polls. The Des Moines Register yesterday reported that its latest poll had Dole leading Bush 37 percent to 23 percent. The joke among rival campaign operatives and the national press is that if Bond can pull this one off, it'll be nothing short of his Second Coming.

"Not to go into a big political spin -- but Bush is the national front-runner and Bob Dole has made this the functional equivalent of his home state," he says. "There's no shock value if he wins here. But if we pull an upset, there's no place else for him to go. It will finish his candidacy. It's curtains."

Last week, the war escalated, as Bush's Iowa campaign chairman, George Wittgraf, circulated a memo accusing Dole of "mean-spiritedness" and "cronyism."

Making the contest all the more fun for spectators is that Bond's counterpart in the Dole camp is an energetic 30-year-old named Tom Synhorst. Synhorst is a newcomer to presidential politics, but he managed Iowa Sen. Charles Grassley's 1986 reelection race.

"They tell me that he's me eight years ago -- young and hungry," says Bond, now 37. "Well, I say, 'He'd better be real hungry -- because I'm old and feisty.' "

Since 1980, Bond has run the gamut of GOP jobs, from White House staffer (deputy chief of staff for Bush) to Republican National Committee official to political consultant. More than a year ago he rejoined the team, this time as the deputy campaign manager, under Lee Atwater. He's known as the detail man, able to mobilize a state lickety-split, while Atwater's forte is strategy.

Some say that after the Ames poll, it was Barbara Bush who asked him to return to Iowa. But Bond will only confirm that he spoke to all four of Bush's sons and that there was a "consensus."

"It was the right decision for them -- but a tough family decision for me," says Bond, whose wife and two sons are in Washington. He tries to commute home at least twice a month. "It's been tough . . ."

What's important now, Bond says, is to keep up staff morale, making sure Bush's remaining appearances here go smoothly ("we can't have dog events with the national media on top of us") and, most important, persuading Bush supporters to attend the caucuses. The one unknown here is how well Robertson will mobilize his troops.

"When I managed this in '80, people said, 'Oh, these guys were so smart' -- it was common sense," he says. "It's retail politics. We have to get to these people one by one."

Bond insists that he's one operative who doesn't dream about the White House. Win or lose in November, he and his family are moving to their new house on Long Island. Not that he wouldn't dabble in a bit of consulting come 1989. Still, he insists, "politics is a great living -- but it's a lousy life. I'm outta Washington."

The Home Town Girl Teresa Vilmain, Dukakis' aide, is an unusual breed of Iowa campaign junkie. She's 29, hails from Cedar Rapids and actually grew up in a home where caucuses were held quadrennially (today, caucuses are usually held in public buildings). She has spent almost her entire adult life organizing statewide campaigns -- trying to finish up at the University of Iowa in between. "Can you believe I still have 17 hours left?" she asks incredulously. "I'm going to be 30 years old. It might be time to stop running around."

Not much chance of that. Vilmain started this election cycle as Gary Hart's state coordinator. When he dropped out of the race last May, following the Donna Rice incident, Vilmain was treated like the hottest political property in the state. Every Democratic presidential campaign "made a pass," she says, to the point where she finally went into self-imposed exile to think things through.

"I basically left my answering machine on and went swimming," she recalls during an interview at Dukakis headquarters. "It wasn't as if I had this big soul-searching decision about which one to go with -- I liked Dukakis -- I just didn't know if I wanted to stay in the campaign at all."

She says she hates talking about that period because it overemphasizes her value. "There wasn't a straw poll, so we became the value system," she says. "It became a show of strength to get Hart's staff."

Perhaps. But those who know Vilmain say she's more than worth her $35,000 salary. Her schoolgirlish demeanor belies her tightly wound intensity when it comes to electoral politics. Last December, The Wall Street Journal named her one of the political stars of the year 2000. And when it comes to Iowa, there are few as experienced: She worked in Ted Kennedy's presidential race here in 1980 and managed Sen. Tom Harkin's 1986 Senate race.

She not only knows every back road, she understands Iowans' concerns and, most certainly, knows as well as anyone how to get registered Democrats out to vote tonight.

What she brought to "the Duke," she says, was the ability to "localize the campaign faster." Dukakis is widely thought to have one of the best organizations in the state.

"We had more people in the field, setting up regional offices and getting out his message before the other candidates," she says. "That becomes important when you have a sitting governor who simply can't be here as much as the others."

Vilmain says she understands why some political observers believe the caucuses are overplayed, with the estimated 250,000 caucus-goers not wholly representative of the state's 2.8 million population. "I think the system needs to be evaluated when there is more emphasis on the process than on the candidates," she says.

Vilmain realizes that her man must make a respectable showing as he heads into New Hampshire, where he is favored to win the Feb. 16 primary. Last week, Dukakis told reporters he'd be happy to come in second in Iowa, but yesterday's Register poll showed him trailing both Rep. Richard Gephardt and Sen. Paul Simon. "This is not a do-or-die state," Vilmain says, "but he has to do well. You want him to go on to New Hampshire with a nice send-off."

Every day the tension mounts. At a press briefing at Drake University last week, Dukakis was asked about reports that a member of his staff was fired for spying on the Paul Simon camp. He implied that Simon staffers had infiltrated his campaign earlier. When pressed, he bolted from the podium, saying Teresa Vilmain would explain. In a testy exchange with reporters, Vilmain refused to name names, snapping, "I am not going to ruin someone's political career. Ask the Simon campaign." She then stormed off, leaving reporters fuming.

It's unclear what's next for her. After shutting down the Dukakis operation here, she may precede the campaign to the South, maybe Texas. If he wins the presidency, she's not so sure a job in Washington is her thing. "I like Iowa," she says.

Indeed, Vilmain has only once left the state for an extended period: to manage former Pennsylvania congressman Bob Edgar's unsuccessful bid for the Senate. For the two years she worked on the race, she kept a map of Iowa on the wall over her desk.

The Hungry Youngster The low point for Laura May came last July, when former Arizona governor Bruce Babbitt bombed during a televised debate from Houston. (He came across jittery and somewhat inarticulate.)

"For three or four weeks, all I did was field calls . . . trying to convince people, 'Yes, he can communicate on television, he can be an effective president' . . . I spent the entire time on the defensive . . . It was terribly draining."

May survived, but there were other crises, like driving in her first blizzard. She grew up in Arizona and attended college at Claremont McKenna in California, where snow is only something you see in photographs.

"I was terrified," she says. "The car was low on gas and I couldn't see two inches in front of me . . . Now I never leave Des Moines without a bag of sand and some blankets."

Laura May is what these campaign staffs are all about. She moved here as Babbitt's first on-site gofer in July 1986, a month out of college. She was an American studies major looking for big-time experience. "I was told {by Babbitt officials} to make the kind of friendships that will last through the caucuses," she says.

Right off, she realized she had to buy a car and spend $200 of her $800 monthly net income on car payments. Another $200 goes toward rent. "I'm always worried about my bills -- afraid my car will get repossessed," she says.

Her Chevy Nova is still humming, and in the past year and a half it has crisscrossed the state a dozen times, stopping at county courthouses, women's clubs and churches.

May also opened Babbitt's first office here, compiled hundreds of lists on the computer and learned to live with a phone on her ear. These days, she is in charge of Polk County (which includes Des Moines), keeping track of the 154 caucus sites. Her entire life now is the Iowa campaign. She dates a man from Jesse Jackson's office.

And after the never-ending days and subsistence wages, what can she possibly be thinking when the Des Moines Register poll has Babbitt still in the single digits?

"I don't let myself think about losing," she says. "I don't really believe it will happen . . . There are a lot of Babbitt supporters out there, and they are the people who traditionally attend the caucuses."

She says she never entertains the possibility that she may have to return to her parents' home in Phoenix. "I'd like to go down south and organize a state for him," she says.

And if he wins the Big One?

"Well, I don't know much about how the White House is organized, but I'd like to have a job that helps Governor Babbitt keep in touch with his supporters around the country. I'm definitely interested in a political-type job. I'll be doing this kind of work for a while. I think it's in my blood."