Sen. Kyrsten Sinema says she's leaving the Democratic Party to register as independent

Arizona Sen. Kyrsten Sinema has announced she’s switching her party affiliation to independent, although Democrats will still hold control of the chamber.

In an interview with Politico published Friday, Sinema said she would not be caucusing with Republicans and expected to keep her subcommittee chairmanships, meaning the 51-49 Democratic majority for next year would stay intact. In that same interview, she declined to say whether she was running for reelection.

Sinema explained her decision in an Arizona Republic op-ed, writing, “When politicians are more focused on denying the opposition party a victory than they are on improving Americans’ lives, the people who lose are everyday Americans. That’s why I have joined the growing numbers of Arizonans who reject party politics by declaring my independence from the broken partisan system in Washington.”

White House press secretary Karine Jean-Pierre released a statement calling Sinema a “key partner on some of the historic legislation President Biden has championed over the last 20 months,” noting her votes for the American Rescue Plan and the Inflation Reduction Act (which required the support of all 50 Democratic senators in unison) as well as legislation on gun safety and protecting same-sex and interracial marriage.

“We understand that her decision to register as an independent in Arizona does not change the new Democratic majority control of the Senate, and we have every reason to expect that we will continue to work successfully with her,” Jean-Pierre added.

Sinema becomes the third independent in the U.S. Senate, joining Bernie Sanders of Vermont and Angus King of Maine — both of whom caucus with Democrats. The last senator to switch party affiliation was Pennsylvania’s Arlen Specter, who switched from Republican to Democrat in 2009 to avoid the prospect of a difficult GOP primary.

Sinema’s election in 2018 began a string of Democratic wins in Arizona that included Biden’s win there in 2020, two Senate victories by Mark Kelly and a win by Katie Hobbs in the 2022 gubernatorial race. Sinema, however, has alienated and annoyed Arizona Democrats by hindering parts of the Biden agenda repeatedly over the first two years of his term. After initially positioning herself as a progressive, she has shifted to the center and earned the praise of Senate Minority Leader Mitch McConnell, R-Ky.

Polling has shown that Sinema would likely have had a difficult time surviving a Democratic primary challenge from Rep. Ruben Gallego, a Marine veteran who represents the Phoenix area and is a member of the Congressional Progressive Caucus. Gallego criticized Sinema last month for doing “nothing” to help the party in the midterms. If she were to run for reelection as an independent, Democrats would have to decide whether to challenge her in a three-way race and potentially make it easier for a Republican to flip the seat.

Sinema’s refusal to support the elimination of the legislative filibuster in the Senate, which requires 60 votes to pass most laws, has drawn particular ire. The filibuster is not mentioned in the Constitution and was historically used to block civil rights legislation. When Sinema refused to alter the filibuster to pass a voting rights bill earlier this year, she was censured by members of the Arizona Democratic Party executive committee. Earlier this year, Democrats altered the Inflation Reduction Act to strip out taxes on hedge funds and private equity firms in order to earn Sinema’s vote.

Emily’s List, an organization that supports female candidates who are in favor of reproductive rights, released a statement in January criticizing the senator for her pro-filibuster position. It was a dramatic reversal after the group had been her biggest supporter, donating more than $400,000 in her successful 2018 Senate bid.

“Understanding that access to the ballot box and confidence in election results are critical to our work and our country, we have joined with many others to impress upon Senator Sinema the importance of the pending voting rights legislation in the Senate,” Laphonza Butler, the group’s president, said in a statement. “So far those concerns have not been addressed.”

“Right now, Senator Sinema’s decision to reject the voices of allies, partners and constituents who believe the importance of voting rights outweighs that of an arcane process means she will find herself standing alone in the next election,” she added.

In a statement released Friday morning, the Primary Sinema PAC, aimed at defeating her, said, “Today, Kyrsten Sinema told us what we’ve already known for years: she’s not a Democrat, and she’s simply out for herself.

“For the last year, we’ve been laying the groundwork to defeat Kyrsten Sinema because Arizonans deserve a Senator who cares about them, and not special interests. In one way, Sinema just made our jobs easier by bowing out of a Democratic primary she knew she couldn’t win. Now, we’ll beat her in the general election with a real Democrat.”