Sen. Kyrsten Sinema, an Arizona independent, announced Tuesday she will leave the Senate at the end of her term this year, a move that will shake up the battle for control of the chamber in November and remove a key player who has been central to major negotiations in Congress.

Sinema has been an influential yet polarizing figure in the Senate and has frequently worked to broker compromise between Democrats and Republicans. In announcing her decision not to seek reelection, the Arizona senator said, “I believe in my approach, but it’s not what America wants right now.”

Sinema’s decision takes her out of the fight for her seat in an extremely competitive state. Democratic Rep. Ruben Gallego of Arizona and former Arizona Republican gubernatorial nominee Kari Lake are among the most closely watched candidates in the Senate race.

The race in Arizona will be one of the most important in November for determining the majority in the Senate. The state voted for President Joe Biden by a slim margin of less than one percentage point in 2020.