Joni Ernst didn’t know the price of soybeans. Here’s why that could cost her.

In the middle of an unexpectedly close reelection fight, Iowa Sen. Joni Ernst could have used a strong night at a virtual debate Thursday against Democratic challenger Theresa Greenfield. Instead, she bungled a question that her opponent said an Iowa senator should know the answer to.

It started when Greenfield correctly answered a question about the “break-even” price of corn — it’s going for about $3.68 per bushel, she said, and at that price, there might be some farmers who are meeting their production costs. Then the moderator asked Ernst a similar question about the break-even price of soybeans. Ernst answered $5.50, well below the actual price of $10.05. She then complained to the moderator that Greenfield had not been posed the same question.

Greenfield immediately seized on the moment, tweeting that Ernst “should know the price of soybeans.”

The clip quickly blew up on social media, even with most of the political sphere talking about the presidential candidates’ dueling town halls.

The question may have seemed gimmicky to some, but as NBC News political correspondent Sahil Kapur noted, familiarity with local agricultural concerns has been important to Iowa voters in the past. And six years after winning an eight-point victory to secure her first term in the US Senate, Ernst — once viewed as a rising star in the Republican Party — needs those voters.

Both Ernst and Greenfield grew up on farms. Ernst spent 22 years in the Iowa Army National Guard and served in the Iowa State Senate from 2011 to 2014 before being elected to the US Senate, replacing retiring Sen. Tom Harkin.

Greenfield, meanwhile, has never held elected office. After putting herself through college, she has worked as an urban planner and real estate developer in Iowa. But she’s been polling neck-and-neck with the incumbent Ernst, sometimes even a few points ahead.

Iowa has been a bellwether state in recent presidential elections. Barack Obama won the Hawkeye State by nearly 10 percentage points in 2008 and by around 6 points in 2012. But Donald Trump coasted to victory there in 2016, winning by over 9 percentage points.

Democrats, however, appear to have some momentum there now. Before the 2018 midterm elections, Republicans held three of the four US House seats in Iowa, but two of those changed hands in the last cycle. Abby Finkenauer flipped the First District, which covers the northeastern part of the state and includes Cedar Rapids, and Cindy Axne did the same in the Third District, which covers the southwestern part of the state and the capital city of Des Moines.

As Vox’s Dylan Scott explained, Iowa, which is 91 percent white, appeared to be moving permanently to the right after Republican success there in 2014 and 2016. But the more urban and suburban parts of Iowa are growing, which could pose problems for both Ernst and Trump. And Thursday didn’t help. As one Democratic strategist had previously told Scott:

“The thing people like about Joni Ernst, she was real and relatable,” the Democratic strategist said. “Greenfield has that in spades. ... Voters want to vote for somebody they think understands the life they’re leading.”

Will you support Vox’s explanatory journalism?

Most news outlets make their money through advertising or subscriptions. But when it comes to what we’re trying to do at Vox, there are a couple reasons that we can't rely only on ads and subscriptions to keep the lights on.

First, advertising dollars go up and down with the economy. We often only know a few months out what our advertising revenue will be, which makes it hard to plan ahead.

Second, we’re not in the subscriptions business. Vox is here to help everyone understand the complex issues shaping the world — not just the people who can afford to pay for a subscription. We believe that’s an important part of building a more equal society. We can’t do that if we have a paywall.

That’s why we also turn to you, our readers, to help us keep Vox free. If you also believe that everyone deserves access to trusted high-quality information, will you make a gift to Vox today?

One-Time Monthly Annual

$5/month

$10/month

$25/month

$50/month

Other

$

Yes, I'll give $5/month

Yes, I'll give $5/month

We accept credit card, Apple Pay, and Google Pay. You can also contribute via