(CNN) Joni Ernst first captured national attention in the 2014 US Senate race in Iowa, when she aired during the Republican primary an unusual ad. "I grew up castrating hogs on an Iowa farm," she said. "So when I get to Washington, I'll know how to cut pork."
Six years later, the folksy image Ernst has cultivated stands between Democrats and a Senate seat they desire, one of a handful they may need to flip in order to seize control of the chamber this fall. The Senate Majority PAC, the largest Democratic outside group involved in Senate races, is trying to dismantle it, painting Ernst as a Washington insider instead.
The Super PAC will reserve $7.4 million in ads in Iowa this fall, expanding on its initial $13 million effort.
It's unclear what message SMP will strike for the entire last two months of the campaign. But in a new television ad, the group attempts to reverse Ernst's self-proclaimed image as someone who will change Washington to someone whom Washington has changed.
In the ad, a nurse named Polly says that Ernst "isn't willing to stand up to" drug and insurance companies. "Joni Ernst has taken their money and voted to support their agenda," says Polly. "She's lost touch with what it means to be from Iowa."
It is an extension of the fight the two parties have long waged, spending millions attacking Ernst and Democratic Senate candidate Theresa Greenfield as more beholden to corporate interests and dark money groups than the voters in their state.
Similar clashes have broken out in the other top Senate races, including in North Carolina, where End Citizens United launched on Monday a nearly $2 million ad campaign against Republican Sen. Thom Tillis.
But it may hold particular resonance in Iowa, where Democratic groups have been on the air for months attacking Ernst for alleged campaign violations and using them to drive their overall message.
In July, End Citizens United, a group trying to get big money out of politics by reversing the 2010 Supreme Court case that fueled the rise of Super PACs, launched an ad hitting the Ernst campaign for having to pay a $14,500 fine, the largest in Iowa's history, after the FEC found her 2014 campaign "knowingly" accepted "excessive and prohibited contributions" and failed to "timely refund" them. At the end of August, the Senate Democrats' campaign arm aired its first TV ad in Iowa, telling voters that Ernst and her campaign "potentially" violated the law in working with an outside group, according to the Associated Press. The Ernst campaign has vigorously denied the charges.
In response, Republicans have called Greenfield a hypocrite and a liar, zeroing-in on her saying she won't take "one dime" from corporate PACs. While she has not, the Democrat has taken hundreds of thousands of dollars from other groups that do receive corporate donations, according to multiple reports, and money from corporate officials and lobbyists.
"Theresa Greenfield is an out-of-touch liberal who hypocritically lines her pockets with more than $700,000 from corporate lobbyists, executives and CEOs, showing how dishonest she really is," said Ernst spokesman Brendan Conley.
One Ernst ad features a moment in the Democratic primary debate, when candidate Eddie Mauro said to Greenfield, "She says she wants to end corruption, but she's taken corrupt money."
The attacks on Greenfield are less about campaign finance but about her credibility, according to Ernst campaign adviser David Kochel. He said the focus of their attack ads suggest: "If she'll lie about that, what else will she lie about?"
Mauro told CNN in a statement provided by the Greenfield campaign that while they "had some differences" in the primary race, his former opponent is "consistent about her pledge to reject contributions from corporate PACs."
"For a corrupt and lying politician like Senator Ernst to use my comments to falsely attack Theresa is wrong," said Mauro.
The Iowa race is one of the most competitive Senate campaigns this year. Before Ernst won her seat in 2014, Democratic Sen. Tom Harkin held it for 30 years. Democrats need to win the White House and take four Senate seats, expecting that Alabama Democratic Sen. Doug Jones loses his.
The Iowa Senate race is widely expected to be the most expensive of all time. Political groups are prepared to pour over $127 million in ads, according to Kantar's CMAG. In 2014, groups spent $92.6 million, according to the Center for Responsive Politics.
"You can't watch television in Iowa for five minutes without seeing an ad in this race," said Iowa Democratic strategist Matt Paul. "That's sort of the challenge -- punching through in this environment."
SMP has tried to solve that problem by not only spending huge sums of money but also by inserting its anti-special interest streak even in its positive ads. In its first spot in February, a narrator notes that Greenfield grew up on a family farm and raised her two boys as a single mom, concluding that she's "tough enough to take on Washington's corruption and deliver for Iowa."
But since then Iowa has become a hot spot for the pandemic, becoming one of the country's top 10 states for coronavirus cases per 100,000 people, according to data from the Johns Hopkins University Center for Systems Science and Engineering.
After Ernst baselessly said a couple weeks ago that she was skeptical of the US coronavirus data, seeming to agree with a supporter at a rally who thought the number of cases were overcounted, some Democratic operatives said that the pandemic will take even higher prominence in the last months of the campaign.
Ernst has since walked back her remarks, but Greenfield has called on her opponent to apologize to health care professionals.
"Joni Ernst has spent the last six years selling out Iowans and it's made this Senate race one of the most competitive in the country," said SMP spokesman Matt Corridoni. "When she's not pushing Covid conspiracy theories or blaming front line workers for the virus, she's voting to take away Iowans' health care. Joni has lost touch with the people of Iowa and Iowa nurses like Polly aren't going to stand for it."