US Senator Kyrsten Sinema of Arizona announced on Friday that she has left the Democratic Party and registered as an independent, but said she does not plan to vote with Republicans, ensuring Democrats will retain their narrow majority in the Senate.
“Like a lot of Arizonans, I have never fit perfectly in either national party,” Ms Sinema said in an article for The Arizona Republic newspaper.
Ms Sinema models her political approach on the renegade style of the late Republican senator John McCain, also from Arizona, and has frustrated Democratic colleagues at times with her overtures to Republicans and opposition to Democratic priorities.
She said she was “declaring my independence from the broken partisan system in Washington”.
Ms Sinema's departure from the Democratic Party is not entirely surprising, as the first-term senator put up frequent roadblocks to progressive priorities, such as a minimum wage increase or President Joe Biden’s big social spending initiatives.
Still, the White House was quick to praise Ms Sinema, calling her a “key partner” on several important pieces of legislation.
“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,” White House press secretary Karine Jean-Pierre said.
Ms Sinema wrote in The Arizona Republic that she came into office pledging “to be independent and work with anyone to achieve lasting results”.
“I committed [that] I would not demonise people I disagreed with, engage in name-calling, or get distracted by political drama. I promised I would never bend to party pressure.”
She wrote that her approach was “rare in Washington and has upset partisans in both parties” but “has delivered lasting results for Arizona”.
Two other current senators — Bernie Sanders of Vermont and Angus King of Maine — are registered Independents but reliably vote with Democrats.
Together with Mr Sanders and Mr King, the Democrats have 50 reliable votes in the 100-seat Senate, whereas the Republicans only have 49. Even if Ms Sinema decided to vote with the Republicans, the Democrats would still hold a technical majority as Vice President Kamala Harris holds a tie-breaking vote.
Arizona Congressman Ruben Gallego slammed his colleague in a Tweet saying: “Unfortunately, once again Ms Sinema is putting her own interests ahead of getting things done for Arizonans".
Ms Sinema told Politico that she will not caucus with Republicans and that she plans to keep voting as she has since winning election to the Senate in 2018 after three House terms.
“Nothing will change about my values or my behaviour,” she said.
She faces re-election in 2024 and is likely to be matched against a well-funded primary challenger after angering much of the Democratic base. She has not said whether she plans to seek another term.