See if this sounds familiar. Excessive political predictions—some plausible, others intriguing—clutter the news cycle. Enduring perceptions and narratives, held as sacrosanct, are easy copy that support convincing forecasts. The quick bites of analysis come relentlessly—nourishing Twitter feeds, instigating panel discussions, confusing voters. In 2016, pundits, polls, and prose dismissed Donald Trump’s electoral chances. Now, in 2018, ahead of Tuesday’s midterm election, the safe bet says Democrats will take the House of Representatives and Republicans will keep the Senate.

Electoral history suggests the president’s party is likely to lose House seats—even its majority. Since the mid-1940s, only two presidents—Bill Clinton in 1998 and George W. Bush in 2002—saw their parties advance in the House during midterm elections, and they were buoyed by high approval ratings. In the Senate, meanwhile, current theory holds that Republicans can preserve their majority, or even gain seats, because of races in states that supported Trump in the presidential election. But what if an Upper Midwest state, one that Trump won by 36 points, delivered a surprising victory for its incumbent Democratic senator? Most polls suggest North Dakota’s Heidi Heitkamp is finished, but the state’s voters could decide otherwise.

An overlooked recent poll shows Heitkamp leading her Republican opponent, Congressman Kevin Cramer. The Forum, a statewide news outlet, hosted the poll in mid-October, which was conducted by Polco, a digital platform for citizen-focused data. Running on the Forum’s online syndicates, the poll followed Polco’s verification of demographic data. It deviated from the traditional approach to methodology, favoring a sample that provided an improved snapshot of the state.

Heitkamp’s resilience should not shock anyone. Despite its small population (755,000), North Dakota is notorious for producing upsets in electoral politics. A unique approach to voting plays a role—North Dakota is the only state without a voter registration process. But last year, Republican Governor Doug Bergum signed a controversial House bill requiring voters to submit proof of residency. The law subsequently stirred confusion among Native Americans living on reservations. Just last week, a federal judge upheld the existing voter ID law ahead of Election Day. Regardless, it remains difficult to discern the state’s political trends or ideological preferences.

Consider North Dakota’s historical record. Since 1992, voters have favored Republican state candidates while also supporting Democrats for the U.S. Senate and House. For the past quarter century, governors have been Republican. Yet despite the GOP’s lock on state offices, Democrats consistently controlled the single at-large House seat and both Senate seats until 2010. That year’s Republican wave swept Rick Berg, previously the state’s House majority leader, into Congress. In 2012, Berg parlayed his congressional success into a Senate race against Heitkamp. Polls suggested imminent victory for Berg, but Heitkamp prevailed with a one-point victory.

South Dakota offers a similar lesson in political upsets. In 2004, Tom Daschle, the Senate’s Democratic minority leader, faced John Thune, a former GOP congressman, in what became the nation’s most expensive campaign. Polls showed a tight race, but incumbency and influence favored Daschle. Thune defeated Daschle with 51 percent of the vote, once again showing the Dakotas’ unpredictable voting patterns.

As Tuesday approaches, Heitkamp is relying on a massive fundraising advantage over Cramer. In the first 17 days of October, she raised a remarkable $12.5 million, with 60 percent of her contributions coming from small donors. Heitkamp’s vote against Brett Kavanaugh’s Supreme Court nomination played a significant role in her fundraising bump. But this cash infusion turned into campaign insurance when she confronted the fallout of a newspaper advertisement. In the ad, her campaign listed women as survivors of abuse without their knowledge or consent. As CNN reported, one group of women sought “a lawyer who will take our case” because the ad has “interfered with, or downright ruined, our lives.” While Heitkamp faced this communications crisis, Cramer dealt with his own fiasco. In an interview with the New York Times, he called #MeToo a “movement toward victimization.”

Trump’s improbable 2016 victory has lured analysts into another trap. In states like North Dakota, fervent support for the president does not necessarily translate into loyalty to the GOP. The Democratic Party has dramatically evolved, departing from its 20th-century role of representing farmers, big city political machines, and heartland workers raised on the New Deal. Democrats are now in their own trap, taking the opposite position of whatever the Trump administration supports. This leaves heartland voters—many of whom were committed Democrats for generations—alienated and disillusioned. They have found political refuge in Trump, but they don’t necessarily subscribe to GOP edicts. They are inclined to cast votes for individuals over party. Responding to this trend, Heitkamp has run a painstaking and triangulating campaign to maintain their support.

Timothy P. Carney, commentary editor of The Washington Examiner, points to the heartland’s voting complexities in a recent New York Times column. “It’s easy to assume that Rust Belt voters have soured on the president, that blue-collar voters are upset Mr. Trump never Made America Great Again,” Carney writes. “But it’s not about the president: Mr. Trump still has extraordinary high approval ratings among those who voted for him. The problem for the Republicans is that Mr. Trump made these Rust Belt voters into Trump voters, but he never made them Republicans.” According to one Morning Consult poll, Trump’s approval rating remains above 50 percent, but this does not mean that his voters will reject a moderate Democratic senator.

Heitkamp’s survival could create a headache for Republicans. It would increase the importance of defeating incumbent Democrats in states carried by Trump. A Cramer victory, in turn, would nearly guarantee Republicans’ control of the Senate. Economic factors could prove fateful for either party. A recent Bureau of Economic Advisors report showed strong income growth in North Dakota, the third highest behind Texas and Louisiana. If voters attribute the state’s improved economy to Trump, they could reward Cramer. But Trump’s tariffs on China also disproportionately impacted the state’s soybean processors. Resentful farmers may retain Heitkamp for protection.

Whatever happens, the midterm elections are guaranteed to deliver surprises nationwide for Republicans and Democrats. Drawing from the lessons of 2016, it seems facile to write off Heitkamp.

Charles F. McElwee III is a writer based in northeastern Pennsylvania. He’s written for The American ConservativeCity JournalThe AtlanticNational Review, and The Weekly Standard, among others.