OMAHA, Neb. — Even in Nebraska, Sen. Deb Fischer keeps a low profile, earning a reputation as a rancher and public servant who’s more of a workhorse than a show horse.

That solid but inconspicuous image served her well until this fall, when independent candidate Dan Osborn burst onto the state airwaves with edgy ads seeking to redefine the small-town cattlewoman as a corporate huckster.

“The Senate is a bunch of millionaires controlled by billionaires,” says Mr. Osborn in an ad filmed in a warehouse as an electric guitar wails in the background. “My opponent, Deb Fischer, is part of the problem. She’s taken so much corporate cash, she should wear patches like NASCAR.”

The ads playing up Mr. Osborn’s blue-collar vibe — he’s a union organizer and industrial mechanic — have helped turn what was once viewed as a sleepy reelection bid into a tooth-and-nail battle that could determine control of the Senate.

“The first thing I would say about this race is that it’s closer than it should be,” said Randall Adkins, a political science professor at the University of Nebraska Omaha.

“Deb Fischer is a two-term incumbent who has not been involved in some major scandal and is pretty much in line with her party overall,” he said. “One would expect that in a red state like Nebraska, she should be able to get reelected very easily. But there’s clearly something going on.”

The election rankers have taken notice. The Cook Political Report downgraded the race last month from “solid” to “likely Republican,” while Sabato’s Crystal Ball at the University of Virginia’s Center for Politics nudged it from “safe Republican” to “likely Republican.”

In other words, Ms. Fischer, 73, is still the candidate to beat, even though polls show her running neck and neck with the 49-year-old Osborn, the caveat being that virtually all of the polling has been done by the campaigns.

Mr. Osborn is fighting attempts to paint him as a proxy for Democrats.

The Senate’s two Independents — Angus King of Maine and Bernie Sanders of Vermont — both caucus with the Democrats, but Mr. Osborn has said he would prefer to caucus with neither party.

That’s probably unrealistic. “You’ve got to get committee assignments from somebody,” said Mr. Adkins.

A SurveyUSA poll released Tuesday by the Osborn campaign found him ahead by 50% to 44%, with 6% undecided, while a Torchlight Strategies poll released Oct. 10 by the Fischer camp showed her leading by 48% to 42%, with 10% undecided.

The Torchlight analysis by pollster John Rogers said that “nearly a third of voters have not yet realized that Dan Osborn is a Democrat pretending to be an independent,” a key talking point for the Fischer camp.

Republicans have accused Mr. Osborn of being a Democrat in Independent’s clothing, drawing distinctions between the candidates’ stances on issues such as illegal immigration, abortion, and the Senate filibuster, which he has said he would vote to eliminate. There is no Democratic candidate in the race.

“Our recent polling proves that Nebraskans simply don’t agree with Dan Osborn’s support for amnesty, social security for illegal immigrants, extreme abortion, VP Harris’ plan to end the filibuster, or Bernie Sanders,” said Derek Oden, Fischer campaign manager. “We expect this positive trend to continue as time goes on and more Nebraskans learn that Dan Osborn isn’t an independent—he’s a liberal Democrat in disguise.”

The Osborn campaign has fought the Democrat label, even sending a Sept. 30 “cease and desist” letter to the Fischer camp over its characterization of Mr. Osborn as a “liberal Democrat.”

In a state with 334,000 registered Democrats versus 615,000 Republicans, however, Mr. Osborn will need those Democrats, as well as the state’s hefty contingent of 274,000 nonpartisan voters.

Certainly, Democrats are in his corner. The Sixteen Thirty Fund, a group that bankrolls Democrats, has helped fund the Retire Career Politicians PAC, which has spent nearly $5 million to boost Mr. Osborn and $1.9 million to fight Ms. Fischer, according to Open Secrets.

Those cheering for Mr. Osborn include Nebraska Democratic Party chair Jane Kleeb.

“I don’t know [who] made this ad for Osborn but I love it,” Ms. Kleeb said in a Sept. 24 post on X, linking to the NASCAR ad. “Keep it going @OsbornForSenate. Fischer is bought and paid for by corporate folks who don’t care about us.”

Coming to Ms. Fischer’s aid is the ESAFund, or Ending Spending Action Fund, which has dropped a $2 million ad buy calling her opponent “deceptive Dan Osborn.”

Nebraska voters will decide on two Senate candidates in November. Republican Sen. Pete Ricketts is running in a special election to keep his seat after being appointed last year to fill a vacancy, but he’s up by double digits against Democrat Preston Love.

The Ricketts race has been a bright spot for Nebraska Republicans as they struggle to fend off Democrats seeking to take advantage of the “blue dot,” the enclave of left-tilting voters in urban Omaha and the Douglas and Sarpy county suburbs.

Rep. Don Bacon, Nebraska Republican, is locked in a tough reelection battle in the 2nd Congressional District with Democrat Tony Vargas, a rematch of the 2022 race that saw Mr. Bacon eke out a win by 51% to 49%.

Democrats have another reason to keep up the pressure in Omaha. Nebraska allocates electoral votes based on congressional districts, meaning that former President Donald Trump could win the state, as he did in 2016 and 2020, while Vice President Kamala Harris grabs an electoral vote in the 2nd District.

Not hurting Mr. Osborn’s cause is that he shares a last name with Tom Osborne, the legendary University of Nebraska football coach and three-term Republican congressman.

Their names are spelled differently and they are not related, but Mr. Osborne dispelled any uncertainty by endorsing Ms. Fischer in a radio ad released Oct. 2.

 “There’s been a little confusion as one of the Senate candidates, and I share the same last name,” says Mr. Osborne in the ad. “I’ve never met that candidate and know little about him, but I do know Deb Fischer and believe that she’s served Nebraska well in the Senate.”

What could ultimately decide the race are the headwinds from the presidential contest, which is also knotted up in the polls.

“I would say that if Osborn upsets Fischer in Nebraska,” said Mr. Adkins, “then it’s going to be a really long night for Republicans across the country.”

• Valerie Richardson can be reached at vrichardson@washingtontimes.com.