DES MOINES — Sen. Joni Ernst will hold on to her seat in the U.S. Senate after defeating Democratic challenger Theresa Greenfield Tuesday night — marking the end of the second most expensive senate race in U.S. history.

Ernst won 51.6 percent of the vote and Greenfield fell behind with 45.4 percent as of midnight, according to the Associated Press.

Ernst spoke at an Iowa GOP election-night party in Des Moines following her win, saying that in her next six years in Congress she will continue to work on trade deals with foreign countries, support the use of biofuel, and roll back regulations that she said hurt American jobs.

“I will spend the next six years working every single day to live up to what you have given me,” Ernst said. “I also want to say something to every Iowan whether you supported me or not; this has been a very difficult year and a very difficult election for all of us…but the election is over and it’s time to start the healing.”

Ernst said she spoke to Greenfield and congratulated her on a hard-fought campaign.

Greenfield addressed reporters in Des Moines, as well as viewers at home, where she said she counted over 500 days that she was in the race and hopes the nation continues to move forward despite the results.

“While the votes have been counted and our race has fallen short, I did call up Senator Ernst a little bit ago and congratulated her. We always knew this was going to be a close race,” Greenfield said. 

After Greenfield’s win in the June Democratic primary election, Ernst struggled to remain in the lead on polling, consistently falling three to five points behind Greenfield throughout the summer and fall months, according to various polls averaged by FiveThirtyEight. 

Polling of the race varied throughout the election season, but a late Des Moines Register/Mediacom Iowa Poll proved fairly accurate, falling only a few points behind the final result. The poll was a large shift in favor of Republicans across the state compared to previous polls, showing Ernst with 46 percent of support to Greenfield’s 42 percent. 

In the months leading up to the election, Ernst tied her reelection chances to the president and his base,. Iowa saw President Trump winning the state with 53.1 percent of the vote as of midnight. She appeared with Trump at a Dubuque rally in the days leading up to the election. 

Her campaign aired advertisements that leveled inaccurate claims that Greenfield called police officers racist, and that she’s far to the left on health care and the environment. Both candidates flooded streaming platforms, websites, and mailboxes with campaign advertisements.

Spending on the race for the Senate seat from Iowa reached a fever pitch. Ernst beat back a well-funded Democratic opponent, who outraised her four to one in the third quarter of 2020, between July 1 and Sept. 30.

 The Center for Responsive Politics reported that various groups independent of the candidates’ committees spent a total of $107.2 million on the Senate race in Iowa – 53 percent of which went toward supporting Greenfield while 47 percent went toward supporting Ernst. 

Ernst served on the Senate Judiciary Committee during Supreme Court nominee Amy Coney Barrett’s hearings in early October, which took place just a few weeks before the general election.

Several Iowa agriculture groups endorsed Ernst’s reelection campaign including the Iowa Farm Bureau, the Iowa Corn Growers Association, and the Iowa Cattlemen’s Association.

The Iowa Farm Bureau named Ernst a “Friend of Agriculture” in an early September press release, saying Ernst has a proven voting record that aligns with the interests of Iowa farmers and that she supports Farm Bureau policies. 

In March, Ernst voted in support of the Families First Coronavirus Response Act, which provided limited paid sick leave for workers, free COVID-19 testing, and increased funding for Medicaid. She also supported the CARES Act several days later, which allocated $2 trillion toward a nationwide stimulus package.

Bykermark Carver, a 67-year-old retired pastor from Des Moines who attended the watch party, said he wants more Republican control in Congress, despite Republicans already holding a majority in the Senate.

“We need more control of the Senate,” Carver said. “We need more control in Congress to get things done that our President Trump wants to have done.”

Carver specifically named the Speaker of the U.S. House of Representatives Nancy Pelosi as an obstacle for Republican policy.

“I think of Pelosi as the evil witch,” Carver said.

Greenfield held a press-only watch party in Des Moines Tuesday night, and the Republican’s watch party had about 100 attendees.

Iowa Democratic Party Spokesperson, Jeremy Busch, said that this showed how the Democratic watch party prioritized public health above all else. 

“We all want to have some big celebration like it’s done in every single election cycle, but obviously we’re in the middle of a pandemic. Following how Theresa has conducted herself in the campaign, we never want to put an Iowan’s health at risk for our own campaign’s desires,” Busch said. 

Lauren White contributed to this report