Kyrsten Sinema announces she won’t run for Senate seat after leaving Democratic Party

Kyrsten Sinema’s short but lively time in the US Senate is coming to an end.

The one-term senator from Arizona announced on Tuesday that she would serve the remainder of her term before stepping down from the Senate at the end of the year, rather than run for re-election. Following her win in a nail-biter election as a Democrat in 2018, Ms Sinema joined the Senate in January of 2019.

In that one term, she would become one of two holdout senators in the chamber who worked to thwart Joe Biden’s Build Back Better agenda, while also emerging as an opponent to the idea of killing the Senate’s filibuster rule to allow the passage of voting rights legislation. She would go on to drop her party affiliation, becoming an independent, though she continued to caucus with Senate Democrats to protect the party’s majority in the chamber.

Her decision to stand down from a re-election fight comes as she was facing what could have been the political battle of her career. Running as an independent, her continued presence in the 2024 race was set to tee up a three-way fight between herself and the two major-party challengers for her seat — which polling indicates will most likely be Congressman Ruben Gallego for the Democrats, and news-anchor-turned-2020-election-conspiracist Kari Lake for the Republicans.

Ms Sinema’s departure from that expected fight will undoubtedly boost the chances of Mr Gallego or another Democrat in November; the primary elections for the seat will be held in July. Ms Lake, who lost the election for governor in 2022 to Katie Hobbs, would go on to falsely claim that both her election and Donald Trump’s were stolen by the Democrats; she’s now facing a crowded race in her own primary, but has the endorsement of Mr Trump thanks to her vocal defence of him. Equally as important, she also has the backing of the NRSC — the Senate Republican caucus’s campaign arm.

Mr Gallego and Ms Lake both thanked the senator for her service in separate statements on Tuesday, a sign that both are seeking to polish their images among independents ahead of November’s general election.

“I want to thank Senator Sinema for her nearly two decades of service to our state,” said Mr Gallego in a statement released by his campaign. “As we look ahead, Arizona is at a crossroads. Protecting abortion access, tackling housing affordability, securing our water supply, defending our democracy — all of this and more is on the line. That’s why Democrats, Independents, and Republicans alike are coming together and rejecting Kari Lake and her dangerous positions. I welcome all Arizonans, including Senator Sinema, to join me in that mission.”

Ms Lake, whose bombastic warring with opponents of Donald Trump in 2020 and 2021 placed her on the black list of the McCain family and other centrist Republicans in the state, has in particular sought to reform voters’ perception of her. In her campaign announcement, she explained that she was fighting for “honest elections” and to restore “confidence” in voting processes, but avoided explicit mention of her past disproven claims of election fraud.

The departing senator was first elected to the House of Representatives in 2012, having served for eight years in the Arizona state legislature as a representative and later senator. Shedding her ties to the party’s progressive wing which had included a stint with the Arizona Green Party, Ms Sinema would go on to develop a reputation as a conservative Democrat once elected to Congress, joining the Blue Dog Democrats caucus and the bipartisan Problem Solvers as well. This didn’t prevent her from embracing some Democratic Party priorities including the DREAM Act, however.

In the Senate, she doubled down on that rightward shift and came out as a holdout against her party’s effort to carve out an exception to the filibuster to allow the passage of voting rights legislation, which Democrats argue is needed to combat efforts in mostly conservative states to restrict mail-in voting and implement other restrictions for in-person voting. That opposition earned her the ire of major Democratic donors in her state as well as condemnations from groups like Emily’s List, which under the leadership of her now Senate colleague Laphonza Butler pledged to abandon her re-election bid.

Undaunted by anger from within her own party, Ms Sinema would still end up typically voting with the president and remained in the Democratic caucus. She also became one of the architects of a bipartisan infrastructure bill passed into law in 2021.

Her broken ties with both progressive Democrats as well as groups linked more closely to the party’s establishment were not followed by a groundswell of support from moderate Democrats or independents. The incumbent senator consistently trailed both of her major-party challengers and appeared to be set to endanger the seat’s future within the Democratic caucus with her continued bid for re-election. Ms Sinema seemed to recognise this in her video message to Arizonans on Tuesday, explaining that her brand of bipartisanship mixed with opposition to her party’s top priorities was “not what Americans want right now”. The firm acknowledgement also appeared to nip in the bud any talk of running for president or any other office for the time being.

Arizona is one of the key battleground states being fought over by the likely Republican and Democratic candidates, Mr Trump and President Joe Biden, this year after it was one of several states the incumbent Democrat won back from the Republicans in his 2020 victory. With immigration and border security set to be a top campaign issue for both parties, the border state’s politics are likely to make it one of the most talked-about parts of the country as the general election nears.