By Moira Warburton
WASHINGTON (Reuters) - Independent U.S. Senator Kyrsten Sinema of Arizona said on Tuesday that she will not run for reelection in the highly competitive state, which will be critical to her former Democratic Party's chances of maintaining its narrow majority.
Sinema's decision clears the way for an expected head-to-head contest in the November 2024 election between Democratic Representative Ruben Gallego, a former Marine veteran who served in Iraq, and Kari Lake, a far-right Republican who lost a bid for Arizona governor in 2022.
Sinema, 47, was elected in 2018 as a Democrat, but drew her party's ire after she repeatedly foiled policy proposals of President Joe Biden along with moderate Democratic Senator Joe Manchin. They most notably refused to support any change to the Senate's filibuster rule to allow Democrats to enact major voting rights legislation.
Sinema changed her party affiliation to independent in December 2022. She continued caucusing with the Democrats in their 51-49 majority, although she said in subsequent media interviews that she rarely attended caucus meetings even before she formally left the party.
Arizona's races have become among the closest-watched - and most expensive - in the country in recent years. The Senate race between Democratic Senator Mark Kelly and Republican challenger Blake Masters in 2022 saw $129 million spent. Kelly won reelection with 51.4% of the vote.
Her decision not to run will be met with a sigh of relief by Democrats, who will no longer have to worry about her peeling away votes from their candidate and handing the seat to a Republican.
Lake, a former television news anchor, ran in 2022 for governor, narrowly losing to Democrat Katie Hobbs. The Republican still has not conceded defeat, following former President Donald Trump's practice of claiming falsely that his 2020 presidential election loss was the result of widespread voting fraud.
Democrats hold a 51-49 majority in the Senate, when Sinema and two other left-leaning independents are counted among their ranks. The 2024 election is expected to be tough for Democrats, who will be defending several seats in Republican-leaning states.
Manchin, for his part, said in November that he would not be running for reelection and would instead assess public support for "creating a movement to mobilize the middle and bring Americans together."
The expected loss of his seat in heavily Republican-leaning West Virginia increases the pressure on Democrats to maintain control of Arizona's Senate seat.
(Reporting by Moira Warburton; Editing by Scott Malone)