When Sen. Kyrsten Sinema (I-Ariz.) was elected to the U.S. Senate in 2018, she became the first Arizona Democrat to serve in Congress’s upper chamber since 1994.
When she declared herself an independent and left the party in December 2022, her defection dealt a severe blow to Democrats nationwide. It was a public rebuke of Biden administration policies by a key swing-state moderate in a divided Senate.
