Sen. Kyrsten Sinema (I-Ariz.) announced on Tuesday that she will not seek reelection this year, opting out of what would have been a contentious, three-way contest in a swing state that will be consequential for the political balance of the U.S. Senate.

Cut through the 2024 election noise. Get The Campaign Moment newsletter.

Here’s what to know about how Sinema’s decision shakes up the race.

Who is running?

Arizona Sen. Kyrsten Sinema announced what has been obvious for a while now. She’s not running for reelection.

Sadly, I doubt there will be many around the state who will miss her.

She was the first Arizona Democrat in three decades to win a U.S. Senate seat, campaigning on a pledge to work with anybody to get stuff done.

Since then, she’s done just what she promised. She charted a middle course, in search of solutions that have bipartisan support.

Then she learned a hard lesson.

Sen. Kyrsten Sinema’s (I-AZ) decision not to seek reelection to the Senate puts Rep. Ruben Gallego (D-AZ), the likely Democratic nominee, and Kari Lake, who is the front-running Republican candidate, on the fast track for a two-way race in Arizona.

Immediately following the news of Sinema’s retirement, Sen. Steve Daines (R-MT), the leader of the GOP Senate campaign arm, declared the development would improve Lake’s opportunity to flip the seat.