2020 United States Senate election in Iowa

Not to be confused with 2020 Iowa Senate election.

The 2020 United States Senate election in Iowa was held on November 3, 2020, to elect a member of the United States Senate to represent the State of Iowa, concurrently with the 2020 U.S. presidential election, as well as other elections to the United States Senate in other states and elections to the United States House of Representatives and various state and local elections. Primaries were held on June 2.^[1] Incumbent Republican Senator Joni Ernst won re-election for a second term, defeating Democratic nominee Theresa Greenfield.

2020 United States Senate election in Iowa

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Nominee Joni Ernst Theresa Greenfield Party Republican Democratic Popular vote 864,997 754,859 Percentage 51.74% 45.15%

County results Congressional district results Precinct results Ernst:      40–50%      50–60%      60–70%      70–80%      80–90%      >90% Greenfield:      40–50%      50–60%      60–70%      70–80%      80–90%      >90% Tie:      40–50%

U.S. senator before election Joni Ernst Republican Elected U.S. Senator Joni Ernst Republican

Most experts and pollsters considered this race and the concurrent presidential race as a tossup due to incumbent president Donald Trump's low approval ratings and Ernst's own popularity dropping in polls, partly due to a viral moment in a debate where she did not know the break-even price for soybeans.^[2] Despite this, Ernst was reelected by a larger-than-expected 6.6 points, while Trump simultaneously won the state with a similarly unexpected margin of victory. Ernst carried an overwhelming majority of the state's counties including many rural ones, while Greenfield carried only eight counties: Polk, Linn, Scott, Johnson, Black Hawk, Story, Cerro Gordo and Jefferson.^[3]

Republican primary

Candidates

Nominee

• Joni Ernst, incumbent U.S. senator^[4][5][6]

Withdrawn

• Paul Rieck^[7][8]

Endorsements

Joni Ernst

Organizations

• Maggie's List^[9]

Result

Republican primary results^[10]

Party		Candidate	Votes	%
	Republican	Joni Ernst (incumbent)	226,589	98.64%
	Republican	Write-In	3,132	1.36%
Total votes			229,721	100.00%

Democratic primary

On June 2, 2020, Theresa Greenfield won the Democratic primary with 47.71% of the vote, defeating three other major candidates, including Michael Franken, a retired U.S. Navy admiral and former aide to U.S. Senator Ted Kennedy.^{[11][12][13][14][15]}

Candidates

Nominee

• Theresa Greenfield, businesswoman, candidate for Iowa's 3rd congressional district in 2018^[16]

Eliminated in primary

• Michael Franken, retired U.S. Navy admiral and former aide to U.S. Senator Ted Kennedy^[17]
• Kimberly Graham, child welfare attorney^[18][19]
• Eddie Mauro, businessman, teacher, candidate for Iowa's 3rd congressional district in 2018^[20]

Withdrawn

• Cal Woods, journalist and U.S. Navy veteran^[21][22][23] (endorsed Michael T. Franken) (remained on ballot)

Declined

• Cindy Axne, incumbent U.S. representative for Iowa's 3rd congressional district (running for reelection, endorsed Greenfield)^[24]
• Chet Culver, former governor of Iowa^[25]
• Deirdre DeJear, nominee for Secretary of State of Iowa in 2018^[26]
• Abby Finkenauer, incumbent U.S. representative for Iowa's 1st congressional district (running for reelection, endorsed Greenfield)^[27][28]
• Amber Gustafson, candidate for the Iowa Senate in 2018 (endorsed Greenfield)^[29]
• Rita Hart, former state senator and nominee for Lieutenant Governor of Iowa in 2018 (running in Iowa's 2nd congressional district)^[6][30][31]
• Rob Hogg, state senator^[6][30]
• Liz Mathis, state senator^[32]
• Rob Sand, Iowa State Auditor^[6][33]
• J.D. Scholten, nominee for Iowa's 4th congressional district in 2018 (running in Iowa's 4th congressional district)^[34]
• Tom Vilsack, former governor of Iowa and former U.S. Secretary of Agriculture^[35]
• Stacey Walker, Linn County supervisor (endorsed Graham)^[36][37]
• Steve Warnstadt, former state senator and intelligence officer in the Iowa Army National Guard^[6][30]

Debates

Host network	Date	Link(s)	Participants
			Theresa Greenfield	Michael T. Franken	Kimberly Graham	Eddie Mauro
Iowa PBS	May 18, 2020	[38]	Present	Present	Present	Present

Endorsements

Michael Franken

Federal officials

• Chuck Hagel, former U.S. Secretary of Defense (2013–2015) and U.S. Senator from Nebraska (1997–2009)^[39] (Republican)

Kimberly Graham

Individuals

• Paula Jean Swearengin, Democratic nominee in 2020 West Virginia U.S. Senate race^[40]

Organizations

• Association of Professional Flight Attendants^[40]
• Brand New Congress^[41]
• Sunrise Movement Cedar Rapids Chapter^[42]
• Sunrise Movement Dubuque Chapter^[40]
• Sunrise Movement University of Iowa Chapter^[40]

Theresa Greenfield

Federal officials

• Sherrod Brown, U.S. senator from Ohio^[43]
• Abby Finkenauer, U.S. representative (IA-01)^[28]
• Gabby Giffords, former U.S. representative (AZ-08) (2007–2012)^[44]
• Dave Loebsack, U.S. representative (IA-02)^[45]
• Barack Obama, former U.S. President^[46]

State officials

• Marti Anderson, state representative^[44]
• Tony Bisignano, state senator^[44]
• Joseph Bolkcom, state senator^[44]
• Robert Dvorsky, former state senator (1995–2019) and state representative (1987–1995)^[44]
• Ro Foege, former state representative (1996–2008)^[44]
• John Forbes, state representative^[44]
• Bruce Hunter, state representative^[44]
• Pam Jochum, state senator and former Iowa Senate president (2013–2017)^[44]
• Bob Kressig, state representative^[44]
• Monica Kurth, state representative^[44]
• Jim Lykam, state senator^[44]
• Mary Mascher, state representative^[44]
• Jo Oldson, state representative^[44]
• Sally Pederson, former lieutenant governor (1997–2007)^[44]
• Janet Petersen, state senator and Senate Minority Leader^[44]
• Amanda Ragan, state senator^[44]
• Joe Riding, former state representative (2013–2015)^[44]
• Sharon Steckman, state representative^[44]
• Kristin Sunde, state representative^[44]
• Zach Wahls, state senator^[44]
• Cindy Winckler, state representative^[44]

Individuals

• Jon Bauman, Social Security Works PAC president and former Sha Na Na member (1970–1983)^[44]
• Andy McGuire, former Iowa Democratic Party chair^[44]
• Christie Vilsack, former Iowa First Lady (1997–2007)^[44]

Unions

• American Federation of Government Employees^[44]
• American Federation of State, County and Municipal Employees Council 61^[44]
• International Association of Bridge, Structural, Ornamental and Reinforcing Iron Workers Local 89, 67, 111, 577, 21^[44]
• International Brotherhood of Electrical Workers Iowa State Conference^[44]
• International Brotherhood of Teamsters Local 238^[44]
• United Food and Commercial Workers Local 431^[44]

Organizations

• Brady Campaign^[47]
• DSCC^[48]
• EMILY's List^[49]
• End Citizens United^[50]
• Feminist Majority PAC^[51]
• Giffords^[52]
• League of Conservation Voters^[53]
• NARAL Pro-Choice America^[54]
• Population Connection^[55]

Polling

Poll source	Date(s) administered	Sample size[a]	Margin of error	Michael Franken	Kimberly Graham	Theresa Greenfield	Eddie Mauro	Undecided
Public Policy Polling[56]	May 5–6, 2020	849 (V)	–	12%	4%	43%	4%	36%
Emerson College[57]	October 13–16, 2019	317 (LV)	± 5.5%	6%	4%	11%	6%	74%

Results

County results
Results by county:

  Greenfield—70–80%

  Greenfield—60–70%

  Greenfield—50–60%

  Greenfield—40–50%

  Greenfield—<40%

  Franken—<40%

Democratic primary results^[10]

Party		Candidate	Votes	%
	Democratic	Theresa Greenfield	132,001	47.71%
	Democratic	Michael T. Franken	68,851	24.88%
	Democratic	Kimberly Graham	41,554	15.02%
	Democratic	Eddie Mauro	30,400	10.99%
	Democratic	Cal Woods (withdrawn)	3,372	1.21%
	Democratic	Write-In	514	0.19%
Total votes			276,692	100.00%

Other candidates

Rick Stewart, the Libertarian nominee

Libertarian Party

Nominee

• Rick Stewart, Libertarian nominee for the 2018 Iowa Secretary of Agriculture election and independent candidate for the 2014 United States Senate election in Iowa^[58]

Independents

Declared

• Suzanne Herzog, economist and former ER nurse^[59]

General election

Major media described the campaign as one of the most likely to decide control of the Senate after the 2020 election.^[60][61] Polls conducted after the primary showed a close contest between Greenfield and Ernst, with neither candidate leading by more than 4 points.^{[62][63][64][65]}

Through June 2020, Greenfield had raised $11.5 million, compared to $14.6 million for Ernst but by September, Greenfield had pulled ahead, raising $40.0 million compared to $21.6 million for Ernst.^[66][67][68] The race was expected to be the most expensive in the state's history,^[69] and the second most expensive Senate race in the United States, after the 2020 United States Senate election in North Carolina, where Cal Cunningham challenged Thom Tillis.^[70]

Debate

Host	Date & time	Link(s)	Participants
			Joni Ernst (R)	Theresa Greenfield (D)
Iowa Press Debates	September 28, 2020	[71]	Present	Present

Predictions

Source	Ranking	As of
The Cook Political Report[72]	Tossup	October 29, 2020
Inside Elections[73]	Tossup	October 28, 2020
Sabato's Crystal Ball[74]	Lean R	November 2, 2020
Politico[75]	Tossup	November 2, 2020
Daily Kos[76]	Tossup	October 30, 2020
RCP[77]	Tossup	October 23, 2020
DDHQ[78]	Tossup	November 3, 2020
538[79]	Tossup	November 2, 2020
Economist[80]	Tossup	November 2, 2020

Additional general election endorsements

Joni Ernst (R)

Organizations

• Campaign for Working Families^[81]
• Huck PAC^[82]

Theresa Greenfield (D)

Federal officials

• Joe Biden, 47th vice president of the United States, 2020 Democratic nominee for president
• Kirsten Gillibrand, U.S. senator from New York^[83]
• Elizabeth Warren, U.S. senator from Massachusetts^[84]

Unions

• National Education Association^[85]
• United Auto Workers^[86]

Newspapers

• Cedar Rapids Gazette^[87]
• Des Moines Register^[88]
• Dubuque Telegraph Herald^[89]
• Iowa City Press-Citizen^[90]
• Quad City Times^[91]

Organizations

• Center for Biological Diversity^[92]
• Climate Hawks Vote^[93]
• Council for a Livable World^[94]
• Democracy for America^[95]
• Everytown for Gun Safety^[96]
• J Street PAC^[97]
• National Committee to Preserve Social Security and Medicare^[98]
• Natural Resources Defense Council Action Fund^[99]

Polling

Graphical summary

Aggregate polling

Theresa Greenfield vs. Joni Ernst
Source of poll aggregation	Dates administered	Dates updated	Theresa Greenfield	Joni Ernst	Other/Undecided[b]	Margin
Real Clear Politics[100]	November 2, 2020	November 3, 2020	45.8%	47.2%	7.0%	Ernst +1.4
270 to Win[101]	November 2, 2020	November 3, 2020	46.6%	47.0%	6.4%	Ernst +0.4

Poll source	Date(s) administered	Sample size[a]	Margin of error	Joni Ernst (R)	Theresa Greenfield (D)	Other/ Undecided
Public Policy Polling[102]	November 1–2, 2020	871 (V)	–	47%	48%	5%
Change Research[103]	October 29 – November 1, 2020	1,084 (LV)	± 3.2%	47%	48%	4%[c]
Civiqs/Daily Kos[104]	October 29 – November 1, 2020	853 (LV)	± 3.7%	47%	50%	2%[d]
Data for Progress[105]	October 27 – November 1, 2020	951 (LV)	± 3.2%	45%	49%	6%[e]
Emerson College[106]	October 29–31, 2020	604 (LV)	± 3.9%	48%[f]	51%	2%[g]
InsiderAdvantage (R)[107][A]	October 30, 2020	400 (LV)	± 4.9%	51%	45%	4%[h]
Selzer & Co./Des Moines Register[108]	October 26–29, 2020	814 (LV)	± 3.4%	46%	42%	11%[i]
Quinnipiac University[109]	October 23–27, 2020	1,225 (LV)	± 2.8%	48%	46%	1%[j]
RABA Research[110]	October 21–24, 2020	693 (LV)	± 4%	45%	51%	–
Emerson College[111]	October 19–21, 2020	435 (LV)	± 4.7%	51%[f]	46%	3%[k]
RMG Research[112]	October 15–21, 2020	800 (LV)	± 3.5%	43%[l]	46%	10%[m]
				41%[n]	48%	10%[m]
				45%[o]	45%	10%[m]
Siena College/NYT Upshot[113]	October 18–20, 2020	753 (LV)	± 3.9%	45%	44%	12%[p]
Insider Advantage (R)[114][A]	October 18–19, 2020	400 (LV)	± 4.9%	43%	48%	8%[q]
Monmouth University[115]	October 15–19, 2020	501 (RV)	± 4.4%	47%	47%	5%[r]
		501 (LV)[s]		47%	49%	–
		501 (LV)[t]		45%	51%	–
Data for Progress (D)[116]	October 8–11, 2020	822 (LV)	± 3.4%	43%	47%	10%[u]
YouGov/CBS[117]	October 6–9, 2020	1,022 (LV)	± 3.5%	43%	47%	10%[v]
Opinion Insight (R)[118][B]	October 5–8, 2020	800 (LV)	± 3.46%	47%[f]	45%	8%[w]
Civiqs/Daily Kos[119]	October 3–6, 2020	756 (LV)	± 3.9%	46%	49%	6%[x]
Quinnipiac University[120]	October 1–5, 2020	1,205 (LV)	± 2.8%	45%	50%	5%[j]
Data for Progress (D)[121]	September 23–28, 2020	743 (LV)	± 3.6%	42%[l]	44%	14%[y]
				45%[z]	46%	9%[aa]
Hart Research Associates (D)[122][C]	September 24–27, 2020	400 (LV)	± 4.9%	48%	48%	–
RABA Research[123]	September 23–26, 2020	780 (LV)	± 4%	39%	51%	–
Monmouth University[124]	September 18–22, 2020	402 (RV)	± 4.9%	47%	47%	5%[ab]
		402 (LV)[s]		46%	49%	5%[ac]
		402 (LV)[t]		47%	48%	5%[ac]
Siena College/NYT Upshot[125]	September 16–22, 2020	501 (LV)	± 4.99%	40%	42%	19%[ad]
Selzer/Des Moines Register[126]	September 14–17, 2020	658 (LV)	± 3.8%	42%	45%	12%[ae]
Fabrizio Ward/Hart Research Associates[127][D]	August 30 – September 5, 2020	800 (LV)	± 3.5%	50%	45%	5%[af]
Opinion Insight (R)[128][B]	August 30 – September 2, 2020	800 (LV)	± 3.46%	49%[f]	43%	7%[ag]
Public Policy Polling[129]	August 13–14, 2020	729 (V)	± 4.1%	45%	48%	8%[ah]
Monmouth University[130]	July 30 – August 3, 2020	401 (RV)	± 4.9%	48%	45%	6%[ai]
		401 (LV)[s]		48%	47%	6%[ai]
		401 (LV)[t]		48%	47%	5%[aj]
Data for Progress[131]	July 24 – August 2, 2020	1,101 (LV)	± 3.2%	43%	45%	11%[ak]
RMG Research[132]	July 27–30, 2020	500 (RV)	± 4.5%	36%	40%	24%[al]
Spry Strategies (R)[133][E]	July 11–16, 2020	701 (LV)	± 3.7%	43%	45%	12%[am]
GQR Research (D)[134][F]	June 23–28, 2020	800 (LV)	± 3.5%	47%	49%	4%
Selzer/Des Moines Register[135]	June 7–10, 2020	674 (LV)	± 3.8%	43%	46%	11%
Civiqs/Daily Kos[136]	June 6–8, 2020	865 (RV)	± 3.8%	45%	48%	6%
Public Policy Polling (D)[137][G]	June 3–4, 2020	963 (V)	± 3.4%	43%	45%	12%
Public Policy Polling[138]	April 30 – May 1, 2020	1,222 (V)	± 2.8%	43%	42%	14%
Public Policy Polling (D)[139][F]	December 13–15, 2019	944 (V)	± 3.4%	47%	41%	12%
Emerson College[57]	October 13–16, 2019	888 (RV)	± 3.2%	47%	40%	14%
Lake Research Partners (D)[140][H]	April 24–29, 2019	500 (LV)	± 4.4%	56%	34%	–

Poll source	Date(s) administered	Sample size[a]	Margin of error	Joni Ernst (R)	Eddie Mauro (D)	Undecided
RABA Research/Eddie Mauro[141][H]	May 7–9, 2020	632 (LV)	± 3.9%	42%	42%	–
Lake Research Partners (D)[140][H]	April 24–29, 2019	500 (LV)	± 4.4%	58%[l]	33%	–
				49%[an]	44%	–

Poll source	Date(s) administered	Sample size[a]	Margin of error	Joni Ernst (R)	Generic Democrat	Undecided
Public Policy Polling[142]	April 29–30, 2019	780 (V)	± 3.5%	48%	44%	–
Public Policy Polling (D)[143][I]	June 30 – July 1, 2017	784 (V)	± 3.6%	48%	41%	12%

Poll source	Date(s) administered	Sample size[a]	Margin of error	Joni Ernst (R)	Generic Opponent	Other	Undecided
Des Moines Register/Selzer & Co.[144]	March 2–5, 2020	667 (LV)	± 3.8%	41%	31%	3%[ao]	26%[ap]

Poll source	Date(s) administered	Sample size[a]	Margin of error	Generic Republican	Generic Democrat	Undecided
Lake Research Partners (D)[140][H]	April 24–29, 2019	500 (LV)	± 4.4%	45%	41%	–

Hypothetical polling

with Eddie Mauro

with Joni Ernst and generic Democrat

with Joni Ernst and Generic Opponent

with generic Republican and generic Democrat

Results

State senate district results

2020 United States Senate election in Iowa^[145]

Party		Candidate	Votes	%	±%
	Republican	Joni Ernst (incumbent)	864,997	51.74%	−0.36%
	Democratic	Theresa Greenfield	754,859	45.15%	+1.39%
	Libertarian	Rick Stewart	36,961	2.21%	+1.48%
	Independent	Suzanne Herzog	13,800	0.83%	N/A
	Write-in		1,211	0.07%	-0.03%
Total votes			1,671,828	100.0%
	Republican hold

By county

By county

County[146] Joni Ernst Republican Theresa Greenfield Democratic Rick Stewart Libertarian Suzanne Herzog Independent Write-in Margin Total votes # % # % # % # % # % # % Adair 2,809 67.78 1,207 29.13 89 2.15 36 0.87 3 0.07 1,602 38.66 4,144 Adams 1,497 69.34 594 27.51 46 2.13 19 0.88 3 0.14 903 41.82 2,159 Allamakee 4,478 61.04 2,602 35.47 175 2.39 80 1.09 1 0.01 1,876 25.57 7,336 Appanoose 4,189 65.60 1,956 30.63 168 2.63 71 1.11 2 0.03 2,233 34.97 6,386 Audubon 2,188 64.89 1,092 32.38 70 2.08 21 0.62 1 0.03 1,096 32.50 3,372 Benton 8,830 60.93 5,202 35.90 331 2.28 120 0.83 9 0.06 3,628 25.03 14,492 Black Hawk 29,222 44.27 34,963 52.96 1,301 1.97 490 0.74 37 0.06 -5,741 -8.70 66,013 Boone 8,315 54.74 6,316 41.58 385 2.53 167 1.10 7 0.05 1,999 13.16 15,190 Bremer 8,196 56.72 5,911 40.91 254 1.76 84 0.58 5 0.03 2,285 15.81 14,450 Buchanan 6,063 56.64 4,292 40.10 248 2.32 96 0.90 5 0.05 1,771 16.55 10,704 Buena Vista 4,724 59.09 3,022 37.80 166 2.08 75 0.94 7 0.09 1,702 21.29 7,994 Butler 5,291 66.06 2,474 30.89 173 2.16 69 0.86 2 0.02 2,817 35.17 8,009 Calhoun 3,513 67.40 1,531 29.37 129 2.48 32 0.61 7 0.13 1,982 38.03 5,212 Carroll 7,245 64.91 3,580 32.07 230 2.06 96 0.86 11 0.10 3,665 32.83 11,162 Cass 4,725 65.95 2,259 31.53 120 1.67 54 0.75 7 0.10 2,466 34.42 7,165 Cedar 5,935 56.30 4,300 40.79 226 2.14 74 0.70 6 0.06 1,635 15.51 10,541 Cerro Gordo 11,339 48.19 11,534 49.02 430 1.83 211 0.90 16 0.07 -195 -0.83 23,530 Cherokee 4,214 65.59 2,002 31.16 138 2.15 67 1.04 4 0.06 2,212 34.43 6,425 Chickasaw 4,024 61.16 2,324 35.32 159 2.42 71 1.08 2 0.03 1,700 25.84 6,580 Clarke 2,906 63.05 1,520 32.98 119 2.58 60 1.30 4 0.09 1,386 30.07 4,609 Clay 5,716 64.46 2,861 32.26 193 2.18 89 1.00 9 0.10 2,855 32.19 8,868 Clayton 5,845 61.37 3,434 36.06 157 1.65 82 0.86 6 0.06 2,411 25.31 9,524 Clinton 12,559 51.57 10,942 44.93 635 2.61 200 0.82 15 0.06 1,617 6.64 24,351 Crawford 4,424 63.12 2,336 33.33 160 2.28 80 1.14 9 0.13 2,088 29.79 7,009 Dallas 28,727 51.69 25,427 45.75 1,006 1.81 381 0.69 33 0.06 3,300 5.94 55,574 Davis 2,728 67.51 1,167 28.88 112 2.77 32 0.79 2 0.05 1,561 38.63 4,041 Decatur 2,439 65.21 1,165 31.15 90 2.41 43 1.15 3 0.08 1,274 34.06 3,740 Delaware 6,454 64.96 3,235 32.56 172 1.73 71 0.71 4 0.04 3,219 32.40 9,936 Des Moines 9,468 48.27 9,296 47.39 591 3.01 232 1.18 29 0.15 172 0.88 19,616 Dickinson 7,149 63.92 3,791 33.90 174 1.56 66 0.59 4 0.04 3,358 30.03 11,184 Dubuque 26,034 49.05 25,433 47.91 1,148 2.16 428 0.81 37 0.07 601 1.13 53,080 Emmet 2,965 61.81 1,637 34.13 147 3.06 47 0.98 1 0.02 1,328 27.68 4,797 Fayette 5,865 58.06 3,912 38.73 229 2.27 89 0.88 7 0.07 1,953 19.33 10,102 Floyd 4,181 52.45 3,498 43.88 187 2.35 98 1.23 8 0.10 683 8.57 7,972 Franklin 3,270 64.55 1,639 32.35 100 1.97 50 0.99 7 0.14 1,631 32.20 5,066 Fremont 2,563 67.31 1,099 28.86 89 2.34 56 1.47 1 0.03 1,464 38.45 3,808 Greene 3,063 61.36 1,784 35.74 104 2.08 39 0.78 2 0.04 1,279 25.62 4,992 Grundy 4,900 67.90 2,120 29.38 154 2.13 38 0.53 5 0.07 2,780 38.52 7,217 Guthrie 4,103 64.86 2,000 31.62 162 2.56 56 0.89 5 0.08 2,103 33.24 6,326 Hamilton 4,679 59.42 2,913 36.99 190 2.41 84 1.07 9 0.11 1,766 22.43 7,875 Hancock 4,004 65.86 1,881 30.94 130 2.14 60 0.99 5 0.08 2,123 34.92 6,080 Hardin 5,639 63.80 2,920 33.04 195 2.21 84 0.95 1 0.01 2,719 30.76 8,839 Harrison 5,059 63.10 2,574 32.10 253 3.16 118 1.47 14 0.17 2,485 30.99 8,018 Henry 5,875 60.12 3,457 35.38 310 3.17 116 1.19 14 0.14 2,418 24.74 9,772 Howard 2,716 55.36 2,014 41.05 118 2.41 58 1.18 0 0.00 702 14.31 4,906 Humboldt 3,671 69.74 1,443 27.41 108 2.05 40 0.76 2 0.04 2,228 42.33 5,264 Ida 2,757 72.23 964 25.26 66 1.73 28 0.73 2 0.05 1,793 46.97 3,817 Iowa 5,794 60.13 3,541 36.75 205 2.13 84 0.87 11 0.11 2,253 23.38 9,635 Jackson 6,175 56.58 4,249 38.94 366 3.35 118 1.08 5 0.05 1,926 17.65 10,913 Jasper 11,405 56.95 7,905 39.47 531 2.65 167 0.83 18 0.09 3,500 17.48 20,026 Jefferson 4,008 45.50 4,547 51.62 163 1.85 80 0.91 10 0.11 -539 -6.12 8,808 Johnson 23,773 28.77 57,063 69.06 1,382 1.67 373 0.45 42 0.05 -33,290 -40.29 82,633 Jones 6,320 57.97 4,237 38.86 273 2.50 68 0.62 4 0.04 2,083 19.11 10,902 Keokuk 3,565 68.39 1,489 28.56 101 1.94 53 1.02 5 0.10 2,076 39.82 5,213 Kossuth 5,957 66.14 2,799 31.08 193 2.14 57 0.63 0 0.00 3,158 35.07 9,006 Lee 8,489 51.29 7,445 44.98 485 2.93 122 0.74 11 0.07 1,044 6.31 16,552 Linn 53,248 42.10 69,125 54.66 3,188 2.52 815 0.64 90 0.07 -15,877 -12.55 126,466 Louisa 3,259 61.97 1,804 34.30 141 2.68 51 0.97 4 0.08 1,455 27.67 5,259 Lucas 3,105 68.32 1,302 28.65 99 2.18 36 0.79 3 0.07 1,803 39.67 4,545 Lyon 5,522 81.80 1,073 15.89 104 1.54 50 0.74 2 0.03 4,449 65.90 6,751 Madison 6,245 64.25 3,168 32.59 218 2.24 86 0.88 3 0.03 3,077 31.66 9,720 Mahaska 7,860 70.00 2,969 26.44 273 2.43 118 1.05 8 0.07 4,891 43.56 11,228 Marion 12,211 64.06 6,269 32.89 423 2.22 144 0.76 15 0.08 5,942 31.17 19,062 Marshall 9,057 50.68 8,187 45.81 442 2.47 165 0.92 21 0.12 870 4.87 17,872 Mills 5,347 65.54 2,544 31.18 177 2.17 82 1.01 8 0.10 2,803 34.36 8,158 Mitchell 3,347 57.69 2,282 39.33 124 2.14 49 0.84 0 0.00 1,065 18.36 5,802 Monona 3,054 65.47 1,455 31.19 108 2.32 39 0.84 9 0.19 1,599 34.28 4,665 Monroe 2,742 68.40 1,148 28.64 84 2.10 34 0.85 1 0.02 1,594 39.76 4,009 Montgomery 3,633 68.53 1,520 28.67 98 1.85 46 0.87 4 0.08 2,113 39.86 5,301 Muscatine 10,278 50.28 9,381 45.89 570 2.79 199 0.97 13 0.06 897 4.39 20,441 O'Brien 5,675 76.05 1,640 21.98 105 1.41 38 0.51 4 0.05 4,035 54.07 7,462 Osceola 2,525 77.38 657 20.13 49 1.50 31 0.95 1 0.03 1,868 57.25 3,263 Page 5,152 69.27 2,067 27.79 138 1.86 78 1.05 3 0.04 3,085 41.48 7,438 Palo Alto 3,113 63.12 1,677 34.00 106 2.15 36 0.73 0 0.00 1,436 29.12 4,932 Plymouth 10,145 72.26 3,587 25.55 219 1.56 77 0.55 11 0.08 6,558 46.71 14,039 Pocahontas 2,641 69.87 1,003 26.53 91 2.41 39 1.03 6 0.16 1,638 43.33 3,780 Polk 106,443 41.54 142,328 55.54 5,313 2.07 1,985 0.77 188 0.07 -35,885 -14.00 256,257 Pottawattamie 24,720 54.85 18,520 41.10 1,269 2.82 524 1.16 32 0.07 6,200 13.76 45,065 Poweshiek 5,361 53.38 4,381 43.62 202 2.01 91 0.91 8 0.08 980 9.76 10,043 Ringgold 1,870 69.36 732 27.15 75 2.78 16 0.59 3 0.11 1,138 42.21 2,696 Sac 3,849 70.17 1,440 26.25 129 2.35 60 1.09 7 0.13 2,409 43.92 5,485 Scott 42,941 46.88 45,751 49.94 2,139 2.33 709 0.77 66 0.07 -2,810 -3.07 91,606 Shelby 4,489 67.06 1,989 29.71 156 2.33 57 0.85 3 0.04 2,500 37.35 6,694 Sioux 15,785 83.54 2,828 14.97 192 1.02 81 0.43 9 0.05 12,957 68.57 18,895 Story 20,750 41.08 28,216 55.86 1,133 2.24 370 0.73 44 0.09 -7,466 -14.78 50,513 Tama 5,090 56.74 3,588 40.00 205 2.29 79 0.88 8 0.09 1,502 16.74 8,970 Taylor 2,337 72.80 762 23.74 83 2.59 28 0.87 0 0.00 1,575 49.07 3,210 Union 3,820 62.38 2,051 33.49 172 2.81 76 1.24 5 0.08 1,769 28.89 6,124 Van Buren 2,583 68.84 1,065 28.38 75 2.00 28 0.75 1 0.03 1,518 40.46 3,752 Wapello 8,464 55.15 6,344 41.33 394 2.57 132 0.86 14 0.09 2,120 13.81 15,348 Warren 17,276 56.27 12,478 40.64 692 2.25 234 0.76 23 0.07 4,798 15.63 30,703 Washington 6,773 58.12 4,519 38.78 262 2.25 95 0.82 5 0.04 2,254 19.34 11,654 Wayne 2,186 71.55 784 25.66 53 1.73 28 0.92 4 0.13 1,402 45.89 3,055 Webster 10,195 57.81 6,845 38.81 403 2.29 173 0.98 19 0.11 3,350 19.00 17,635 Winnebago 3,336 56.29 2,361 39.84 153 2.58 72 1.21 4 0.07 975 16.45 5,926 Winneshiek 6,039 50.49 5,581 46.66 218 1.82 118 0.99 4 0.03 458 3.83 11,960 Woodbury 24,175 54.27 18,674 41.92 994 2.23 629 1.41 72 0.16 5,501 12.35 44,544 Worth 2,425 55.40 1,803 41.19 98 2.24 46 1.05 5 0.11 622 14.21 4,377 Wright 3,889 62.85 2,063 33.34 158 2.55 76 1.23 2 0.03 1,826 29.51 6,188 Totals 864,997 51.74 754,859 45.15 36,961 2.21 13,800 0.83 1,211 0.07 110,138 6.59 1,671,828 Counties that flipped from Democratic to Republican Clinton (largest municipality: Clinton) Des Moines (largest municipality: Burlington) Dubuque (largest municipality: Dubuque) Floyd (largest municipality: Charles City) Howard (largest municipality: Cresco) Lee (largest municipality: Fort Madison) Worth (largest municipality: Northwood) Counties that flipped from Republican to Democratic Scott (largest municipality: Davenport)

By congressional district

Ernst carried all 4 congressional districts, including one that elected a Democrat.

By congressional district

District[145] Joni Ernst Republican Theresa Greenfield Democratic Rick Stewart Libertarian Suzanne Herzog Independent Write-in Margin Total votes Representative (2020) # % # % # % # % # % # % 1st district 206,559 49.48 197,792 47.72 9,454 2.26 3,231 0.77 267 0.06 8,767 2.10 417,483 Ashley Hinson 2nd district 199,741 49.17 193,588 47.65 9,426 2.32 3,197 0.79 295 0.07 6,153 1.51 406,247 Mariannette Miller-Meeks 3rd district 221,267 48.75 218,756 48.20 9,747 2.15 3,757 0.83 321 0.07 2,511 0.55 453,848 Cindy Axne 4th district 237,430 60.22 144,543 36.66 8,334 2.11 3,615 0.92 328 0.08 92,887 23.56 394,250 Randy Feenstra Totals 864,997 51.74 754,859 45.15 36,961 2.21 13,800 0.83 1,211 0.07 110,138 6.59 1,671,828

See also

• 2020 Iowa elections

Notes

Partisan clients

1. Poll sponsored by The Center for American Greatness, a pro-Trump organization.
2. Poll sponsored by The American Action Forum, which is a 501 organization which usually supports Republican candidates.
3. Poll sponsored by The Human Rights Campaign, which has endorsed Biden prior to this poll's sampling period.
4. Poll sponsored by AARP.
5. This poll's sponsor is the American Principles Project, a 501 that supports the Republican Party.
6. Poll sponsored by the End Citizens United, which has only supported Democratic candidates who are against the landmark Citizens United Supreme Court ruling.
7. Poll sponsored by Emily's List, an organization that supports Democratic female candidates.
8. Poll sponsored by the Eddie Mauro campaign
9. Poll sponsored by Save My Care, a pro-Affordable Care Act organization

Voter samples

1. Key:
   A – all adults
   RV – registered voters
   LV – likely voters
   V – unclear
2. Calculated by taking the difference of 100% and all other candidates combined.
3. Stewart (L) with 2%; "Don't recall" and Undecided with 1%; Herzog (I) and would not vote with 0%
4. Stewart (L) and Undecided with 1%; Herzog (I) and "Someone else" with 0%
5. Herzog (I) with 3%; Stewart (L) with 2%; "Other candidate or write-in" with 1%
6. With voters who lean towards a given candidate
7. "Someone else" with 2%
8. Herzog (I) and Stewart (L) with 1%; Undecided with 3%
9. "Refused" with 4%; "Someone else" and "Undecided/do not remember" with 3%; would not vote with 1%
10. "Someone else" with 1%; Undecided with 4%
11. "Someone else" with 3%
12. Standard VI response
13. "Someone else" with 3%; Undecided with 7%
14. Results generated with high Democratic turnout model
15. Results generated with high Republican turnout model
16. Herzog (I) and Stewart (L) with 2%; "Someone else" and would not vote with 1%; "Undecided/Refused" with 6%
17. Stewart (L) with 5%; Herzog (I) with 0%; Undecided with 3%
18. Herzog (I), "No one" and Stewart (L) with 1%; "Other" with 0%; Undecided with 2%
19. With a likely voter turnout model featuring higher turnout than in the 2016 presidential election
20. With a likely voter turnout model featuring lower turnout than in the 2016 presidential election
21. Stewart (L) with 2%; Herzog (I) with 1%; "Other" with 0%; Undecided with 6%
22. "Someone else" with 2%; Undecided with 8%
23. Would not vote with 1%; "Someone else" with 0%; "Undecided/Refused" with 4%
24. Stewart (L) with 2%; Herzog (I) with 1%; "Someone else" with 0%; Undecided with 3%
25. Herzog (I) and Stewart (L) with 1%; Undecided with 12%
26. If the only candidates were Ernst and Greenfield
27. Undecided with 9%
28. Stewart (L) with 1%; Herzog (I), "Other" and "No one" with 0%; Undecided with 4%
29. Stewart (L) with 1; Herzog (I) with 0%; Undecided with 4%
30. Herzog (I) and Stewart (L) with 2%; would not vote with 1%; "someone else" with 0%; "Undecided/Refused" with 14%
31. "Someone else" with 3%; would not vote with 2%; Undecided with 7%
32. Would not vote with 1%; Undecided with 4%
33. Would not vote with 1%; Undecided with 7%
34. Undecided with 8%
35. Stewart (L) with 2%; Herzog (I) with 1%; Undecided with 3%
36. Stewart (L) and Undecided with 2%; Herzog (I) with 1%
37. "No one" with 11%
38. Undecided with 24%
39. "Another candidate" with 6%; Undecided with 7%
40. Response after pollster addresses respondents with talking points about Ernst and Mauro
41. Would not vote with 3%
42. "Would consider voting for someone else" with 20%; "unsure" with 6%