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Arizona Senate Forecast tossup

Last Updated: Thursday, July 18 at 10:39 AM EDT

Incumbent first-term independent Sen. Kyrsten Sinema, initially elected as a Democrat in 2018 by a margin of 2.3% over then-Republican incumbent Sen. Martha McSally, left the Democratic Party in December 2022. She had initially filed paperwork to run for reelection as an independent but announced in March 2024 that she would not seek a second term. Congressman Ruben Gallego is the presumptive Democratic nominee, while 2022 Republican gubernatorial nominee Kari Lake is the overwhelming favorite to secure the Republican nomination. Early polls assessing the head-to-head contest between Gallego and Lake have shown Gallego with a slight advantage, yet the race is widely considered to be a key battleground given Arizona’s slightly Republican partisan lean. Democrats have won four consecutive statewide federal elections in Arizona and flipped the Governor’s office in 2022, while Republicans control both houses of the Arizona State Legislature and hold a minimum majority in Arizona's U.S. House delegation. Republican presidential candidate Donald Trump won Arizona by 3.5% in 2016, while Democratic presidential candidate Joe Biden prevailed by 0.3% in 2020.