Kyrsten Sinema AP-23351780931987
Her much-anticipated decision ends one of the longest “will she, won’t she” parlor games in Washington. Mark Schiefelbein/AP

Kyrsten Sinema Is Out. Will She Back the Democrat Vying for Her Seat?

She has a tense history with Democratic Senate candidate Rep. Ruben Gallego.

Sen. Kyrsten Sinema finally announced Tuesday that she would not seek reelection, spurred by her sense that her style of legislating is “not what America wants right now.”

The race for her seat in Arizona, likely now between Democrat Ruben Gallego and Republican Kari Lake, could become one of the most expensive and ugliest races in the country. Sinema, a Democrat turned independent, gave a hearty middle finger to partisan politics on her way out the door.

“Because I choose civility, understanding, listening, working together to get stuff done, I will leave the Senate at the end of this year,” she said. Not far from her mind, it seems, was the bipartisan monthslong border deal she played a pivotal role in crafting, only to watch it fall apart several weeks ago, after former President Donald Trump signaled his opposition to it.

Her much-anticipated decision ends one of the longest “will she, won’t she” parlor games in Washington. But waiting this long to decide also had a distinct side effect: It meant Gallego was unlikely to receive official endorsements from top Democrats since Sinema, who still caucuses with them, was still considered an incumbent. It’s unclear if Sinema will ultimately endorse Gallego, but given Arizona’s independent streak, he will need to pick up the support of her would-be voters (as will Lake on the Republican side). But the two have a long relationship rife with animus.

As one Democratic strategist told NOTUS before Sinema made the announcement, “Gallego wants this race to be his as soon as possible. So her last parting gift is making him wait as long as possible.”

Neither Sinema nor Gallego responded to a request for comment or question about a possible endorsement. But as she exited the Senate on Tuesday, a reporter asked if she had “anything to add” to her announcement, and as a staffer responded, “blah, blah, blah,” Sinema simply laughed.

While Sinema has drawn the ire of more progressive Democrats in recent years, Gallego has been one of her biggest critics. In a statement, he thanked her for “nearly two decades of service” to Arizona — but his website still prominently features a banner exclaiming Sinema “betrayed Arizona families,” replete with a GIF of her giving a thumbs-down to a bill to raise the minimum wage.

Gallego and Sinema spent two terms together in the House but did not work together much. Gallego never co-sponsored any Sinema-sponsored legislation during this time. Sinema acted as co-sponsor to Gallego’s bills twice, including on one bill to rename a post office.

After Sinema was elected senator, they never directly sponsored legislation together. However, Gallego has acted as co-sponsor to 20 Sinema-sponsored pieces while she was in the Senate, many Arizona-specific. Sinema has co-sponsored Gallego-sponsored legislation three times, two related to Native Americans. Sources described the relationship as one that ranged from professionally competitive to personal and petty.

Almost all the sources NOTUS spoke with described Sinema as someone who thinks of herself as the “smartest person in the room.” Still, one Arizona Democratic consultant, who was unhappy with Sinema’s party switch, contends her thinking is sometimes justified.

“I got to tell you, in a lot of rooms, she is [the smartest],” the consultant said.

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The differences in Gallego’s and Sinema’s personalities extended to their approaches to legislating. Sinema was strategic about what she said and her relationships with Republicans, and she focused on negotiation and finding compromises.

“She was fond of saying: ‘The more you talk, the less people listen,’ where he would go in guns blazing, and if he didn’t get his way, he would just do it again the next year, trying to wear people down,” the mutual friend said. “And she thought a lot of the time that his approach wasn’t going to yield good results.”

Democrats on Capitol Hill praised Sinema’s willingness to work on big, bipartisan issues and were deferential to the timing of her announcement.

“She gets to choose her own time,” said Sen. Tina Smith when asked if Sinema had waited too long.

While Sen. Brian Schatz said he was looking forward to working with Gallego, he called Sinema a “once-in-a-generation” talent.

“She knows how to make deals. So the institution is going to miss her. Whether they know it or not is a separate question,” he said.

Tara Kavaler is a NOTUS reporter and an Allbritton Journalism Institute fellow. Katherine Swartz, a reporter at NOTUS and an Allbritton Journalism Institute fellow, contributed to this report.