John Thune's hunt for enough votes to oust Senate Minority Leader Thomas A. Daschle has brought him, unannounced, to this town's tiny bowling alley at 3:15 on a recent sunny afternoon. He opens the door to a dark, empty room but soon finds seven men sipping coffee and speculating on the corn harvest in an adjacent cafe.

Thune chats amiably for 20 minutes, never asking for their votes or even reminding them he is the Republican nominee in the nation's most intensely watched Senate race. That, it seems, is needless in a state where he and Daschle are almost universally recognized and their ads blanket television. His next stop: a three-employee tractor-repair shop.

Thune's laconic campaign style might strike some as small-bore. But by most accounts he needs only a few more votes here and there to end Daschle's 26-year congressional career. Besides, Daschle employs the same painstaking campaign style in search of the relative handful of undecided voters in this sprawling state with fewer residents than Prince George's County.

The Senate's Democratic leadership -- and perhaps control of the Senate itself -- will be determined Nov. 2 by a clutch of voters who couldn't swing an alderman's race in many places. The trick is not only to find them but to appeal to them with just the right tone in a state that rivals Iowa for earnest voters who follow politics closely, often know the candidates personally, and are quick to sniff out phoniness or meanness.

Daschle, 56, has mastered the art for a quarter-century. But his challenge is formidable. Everyone agrees President Bush will again win the state handily, and Daschle's party leadership post in Washington often requires him to defend positions too liberal for most South Dakotans. Thune, a former House member personally recruited by Bush to run for the Senate, is a handsome and honed challenger who came within 524 votes of ousting Daschle's protege, Sen. Tim Johnson, two years ago. Bush's name atop the ticket this fall will make up the difference, his supporters hope.

Meanwhile, outside groups such as the U.S. Chamber of Commerce and the GOP's Senate campaign committee are pouring several million dollars into TV ads attacking Daschle, augmenting the more than $6 million Thune has raised for a campaign in which radio and television time is inexpensive. In the end, Daschle hopes the Chamber and other Washington-based groups will misread his constituents and sink Thune with friendly fire. "South Dakotans have a real aversion to negative advertising," he said in an interview between campaign stops in Milbank and Watertown. "They could pay a high price for it."

Referendum on Daschle

In the first of five scheduled debates, Thune and Daschle essentially agreed that the election is a referendum on the senator's tightrope walk between his national Democratic leadership post and his representation of this conservative-leaning state. Daschle said he faithfully brings countless benefits to South Dakota, much as Senate leaders Lyndon B. Johnson and Robert J. Dole did for Texas and Kansas.

"I was in the room when we passed country-of-origin labeling and made it part of the farm bill of 2002," he told the 500 debate attendees packing a tent Aug. 18 at the Dakotafest agricultural trade show near Mitchell. He blamed the Bush administration for later postponing the mandatory labeling, which South Dakota ranchers want in order to help domestic and foreign consumers find U.S.-raised beef.

But Thune, 43, said Daschle is part of Washington's problem, not the solution, because he heads a party that sometimes uses Senate delaying tactics to block GOP-drafted bills and several of Bush's most conservative judicial nominees.

"There is a line where seniority and influence go from being an asset to being a liability," Thune said in a fiery closing statement. "Tom has crossed that line. Because you cannot effectively represent the people of South Dakota when you answer to the liberal Democratic caucus that is made up of Ted Kennedy and Hillary Clinton." South Dakotans must oust Daschle, he said, to end "the blockage and the gridlock in the United States Senate."

The hour-long forum, aired by two radio stations, was to deal only with agriculture issues. But Thune slipped in his support for a constitutional ban on same-sex marriages. Daschle, who opposes the proposed constitutional amendment, focused on topics such as his efforts to require greater use of corn-based ethanol as an automotive fuel component, a big issue in this ethanol-producing state.

Two years ago Thune could not beat Johnson -- a low-profile senator often seen as a Daschle surrogate -- so Democratic loyalists question how he can defeat the real McCoy, a veteran whose clout will grow dramatically if Democrats regain the Senate majority. In an interview between campaign stops in Corsica and Platte, Thune said Daschle's high Democratic profile is the two-edged sword that will undo him. "Daschle is more defined and polarized than Johnson was," Thune said.

And even though his TV ads often refer to Sens. Clinton and Kennedy but not presidential nominee John F. Kerry, Thune hinted that the presidential race may play a bigger role in the weeks ahead. "Daschle will not be able to run away from Kerry," he said.

Daschle Fatigue?

At the Roadhouse Cafe in Watertown, where Daschle would host a community picnic a few hours later, Derek Stone and Lew Tollefson represented the types of voters that worry Democrats. Stone, the 24-year-old manager of cafe's convenience store counter, said he is an undecided voter who leans Democratic. He is sick of campaign commercials and phone calls -- "You can't listen to the radio more than five minutes without hearing one of them," he said -- but he doesn't blame Thune. Daschle "has been there a long time," Stone said, echoing a Thune campaign theme. "I think it's time for somebody else to have a chance, see what they can do."

Lunching at a nearby table, Tollefson, 50, said he has voted for Ronald Reagan, Bush and the president's father but also for Democrats Bill Clinton and George S. McGovern (the last South Dakotan with Daschle's prominence). Like a remarkable number of residents, he has met both Daschle and Thune, and he praised the minority leader for "bringing big [federal] dollars into the state." But Tollefson, who owns a business that makes components for telecommunications products, said he will vote for Thune. "I've met him, I like him. He's a wholesome guy," he said. "I'm not a liberal Democrat. I'm afraid Tom is."

Daschle estimates that about 360,000 of South Dakota's 469,375 registered voters will cast ballots this fall. A recent GOP poll, which showed Daschle with a thin lead, concluded that about 7 percent of the voters are undecided. If so, that means the nearly $12 million Daschle had raised by June 30, plus Thune's $6 million and the sums spent by independent groups (and the sums yet to be raised) are chasing a sliver of persuadable voters, perhaps amounting to $1,000 each.

Daschle, who could be on track to spend $15 million in the race, has been airing TV ads for more than a year touting his work on behalf of the state's farmers, ranchers, retirees and others. He said he does not think Thune's charges of obstructionism will stick because voters realize he has taken principled stands against Bush's efforts to appoint rigidly conservative judges and to tilt tax cuts toward the wealthy. "I think their tax policy has been an abomination," he said in the interview, and several of Bush's judicial nominees "don't deserve confirmation."

Many Daschle supporters are passionate, rhapsodizing about his annual visits to every South Dakota county and his willingness to listen intently to any constituent who wants to talk at any length.

"I've never heard an untrue comment come out of his mouth," Jerry DeWald, 57, a retired naval officer and college classmate of Daschle's, said as he waited at the Watertown picnic to tell the senator hello. But DeWald's 80-year-old mother, Ethel, signaled at the picnic how tough the election might be. A lifelong Republican, she said she plans to vote for Bush and Thune.

For the next 10 weeks, Daschle and Thune will scour the prairies, going door to door and store to store to find a few more Jerry DeWalds and Ethel DeWalds who will have a huge impact 1,200 miles away in Washington for the next six years.

Sen. Thomas A. Daschle responds Aug. 18 during a debate with his Republican challenger, John Thune, left, in Mitchell, S.D.