2018 United States Senate election in Arizona

The 2018 United States Senate election in Arizona took place on November 6, 2018. Incumbent Republican Senator Jeff Flake did not seek reelection to a second term. The election was held concurrently with a gubernatorial election, other elections to the U.S. Senate, elections to the U.S. House of Representatives, and various other state and local elections.

Primaries were held on August 28, 2018, three days after the death of longtime U.S. Senator John McCain. Martha McSally won the Republican nomination, while Kyrsten Sinema won the Democratic nomination. Green Party candidate Angela Green was also on the ballot, but ended her campaign and endorsed Sinema before Election Day.

The Associated Press called the race for Sinema on November 12, 2018, and McSally conceded that day. Sinema became the first Democrat to win a U.S. Senate seat in Arizona since 1988. McSally was subsequently appointed by Governor Doug Ducey to the other vacant Senate seat in Arizona, left open after McCain's death and then held on an interim basis by Jon Kyl.

Background
Arizona, located along the United States border with Mexico, has a unique political history. Upon its admission to the Union in 1912, the state was dominated by Democrats who had migrated there from the South, and aside from the landslide victories of Republicans Warren G. Harding, Calvin Coolidge, and Herbert Hoover, the state voted for Democrats until 1952, when Dwight Eisenhower carried it, and began a lengthy streak of Republican victories interrupted only by Bill Clinton's narrow victory in 1996. Since then, the state had remained Republican, and was won by Donald Trump with a 3.5% margin in 2016, although Trump's margin of victory was much smaller than that of past Republican presidential nominees.

Incumbent Republican Senator Jeff Flake announced in October 2017 that he would retire at the end of his current term instead of seeking reelection for another term in 2018. Flake had previously indicated his intent to run for reelection in March 2017. However, he was considered vulnerable due to persistently low approval ratings, a poor relationship with President Trump, and the threat of a primary challenge from former state senator Kelli Ward, who promised to run on a more pro-Trump platform. Additionally, he had won his first term in 2012 by only 3 percentage points, even though Republican presidential nominee Mitt Romney won Arizona by 9.

On the ballot



 * Joe Arpaio, former Maricopa County sheriff
 * Nicholas N. Glenn (write-in candidate)
 * William Gonzales (write-in candidate)
 * Martha McSally, U.S. representative and retired U.S. Air Force Colonel
 * Kelli Ward, former state senator and candidate for the U.S. Senate in 2016

Failed to file

 * Craig Brittain, owner and co-founder of the revenge porn website IsAnybodyDown?
 * Christian "C.J." Diegel, financial advisor
 * Michelle Griffin
 * Shawn Redd
 * Nicholas Tutora, pharmacist

Withdrew

 * Jeff Flake, incumbent U.S. senator

Declined

 * Andy Biggs, U.S. representative from Arizona's 5th congressional district
 * Jan Brewer, former governor of Arizona
 * Mark Brnovich, attorney general of Arizona
 * Jeff DeWit, treasurer of Arizona (nominated as NASA chief financial officer)
 * Trent Franks, former U.S. representative
 * Paul Gosar, U.S. representative
 * Robert Graham, former chair of the Arizona Republican Party
 * Christine Jones, former GoDaddy executive, candidate for governor in 2014 and candidate for AZ-05 in 2016
 * Bill Montgomery, Maricopa County Attorney
 * Ben Quayle, former U.S. representative
 * Matt Salmon, former U.S. representative and nominee for governor in 2002
 * David Schweikert, U.S. representative from Arizona's 6th congressional district
 * John Shadegg, former U.S. representative

Polling

 * with Jay Heiler


 * with Jeff Flake

Results
[[File:2018 AZ US Senate GOP primary.svg|thumb|200px|Results by county: {{legend|#e27f7f|McSally}}

{{legend|#FFC8CD|30–40%}}

{{legend|#FFB2B2|40–50%}}

{{legend|#E27F7F|50–60%}}

{{legend|#D75D5D|60–70%}} {{legend|#ff9955|Arpaio}}

{{legend|#ffcca9|30–40%}} ]]

On the ballot

 * Deedra Abboud, attorney
 * Kyrsten Sinema, U.S. representative

Failed to file

 * Bob Bishop, pilot
 * Matt Jette
 * David Ruben, physician
 * Chris Russell, attorney
 * Richard Sherzan, retired administrative law judge, former Iowa state representative and candidate for the U.S. Senate in 2016

Withdrew

 * Jim Moss, businessman, activist and former teacher

Declined

 * Randall Friese, state representative
 * Mark Kelly, astronaut, scientist, U.S. Navy captain and husband of former U.S. representative Gabby Giffords (later elected to Arizona's Class 3 Senate seat in 2020)
 * Ann Kirkpatrick, former U.S. representative and nominee for the U.S. Senate in 2016 (running for AZ-2)
 * Greg Stanton, Mayor of Phoenix (running for AZ-9)

Results
[[File:2018 AZ US Senate Democratic primary.svg|thumb|200px|Results by county: {{legend|#7996E2|Sinema}}

{{legend|#6674DE|60–70%}}

{{legend|#584CDE|70–80%}}

{{legend|#3933E5|80–90%}} ]]

Declared

 * Adam Kokesh (write-in candidate), anti-war activist and U.S. presidential candidate in 2020

Removed

 * Doug Marks, veteran and write-in candidate for IL-14 in 2010

Declared

 * Angela Green (write-in candidate)

Removed

 * Eve Reyes-Aguirre, activist

Results
[[File:2018 AZ US Senate Green primary.svg|thumb|200px|Results by county: {{legend|#73bc84|Green}}

{{legend|#005113ff|90-100%}} No votes

{{legend|#999999}} ]]

Debates



 * Complete video of debate, October 15, 2018

Polling

 * with Kelli Ward


 * with Joe Arpaio


 * with generic Republican and generic Democrat


 * with Jeff Flake


 * with Matt Salmon

Results
The race was too close to call on election day. On November 7, 2018 (one day after the election), KGUN 9 reported that McSally held a narrow lead of 0.9%, with thousands of ballots still uncounted. On November 8, Politico reported that Sinema had taken a 9,610-vote lead. Due to the closeness of the vote count, the Associated Press and other major news outlets did not call the race for Sinema until November 12, 2018, six days after the election. McSally conceded the race to Sinema that day. The results were certified on December 3, 2018.

This was the first Senate election won by a Democrat in Arizona since 1988. Sinema is the first woman to be elected to the U.S. Senate from Arizona.

Counties that flipped from Republican to Democratic
 * Maricopa (largest municipality: Phoenix)

Results by congressional districts
Sinema won 5 of the 9 congressional districts.

Aftermath
On December 18, 2018, Governor Doug Ducey appointed McSally to fill Arizona's other Senate seat. The seat was left vacant after the resignation of Jon Kyl, who himself had been appointed following the August 25, 2018 death of John McCain. Both Sinema and McSally were sworn in with the 116th United States Congress on January 3, 2019, marking the first time in history that Arizona was represented by two women in the United States Senate and making Arizona the second state to be represented by two women from different parties. Sinema and McSally are only the second pair of senators from the same state in history to serve together after running against each other the previous year; the first such instance occurred in Oregon in 1996–1997. Ducey stipulated that Sinema would be sworn in first, making her the senior senator; this way, he said, the decision of Arizona's voters would be respected.

Under Arizona law, McSally's appointment was only valid for the duration of the 116th Congress and a special election for her seat was held in November 2020 to determine who would finish the remainder of McCain's unexpired term (which expired in 2023). McSally was defeated by Democrat Mark Kelly in that special election.