Sinema, who left the Democratic Party in December 2022, has not decided if she will seek reelection this year. With nearly $11 million in her campaign account, she remains the biggest unknown on the Senate map. If she does enter the race, it would create an unpredictable three-way matchup.

“Kyrsten remains laser focused on continuing her work making a meaningful impact in the lives of Arizonans across the state – not on campaign politics,” a spokesperson for her campaign said in a statement. “She has the resources to keep delivering lasting results for Arizona.”

The first-term senator has been focused on negotiating a border deal during recent months, keeping her focus and time in Washington. But Sinema’s fundraising steadily declined all year.

Her high-water mark came in the first three months of 2023 when she posted $2.1 million. That fell 22 percent in the second quarter. Then her third-quarter number was only 50 percent of her second-quarter haul. And the new filing shows a 30 percent drop from her third-quarter to fourth-quarter totals.

Sinema’s struggle to fundraise wasn’t for lack of trying, her expenditures suggest. She spent more than $141,000 on digital advertising, which is typically used to attract donors. The campaign also spent more than $124,000 on fundraising consulting and event and travel costs associated with fundraising, the filing showed.

Security-related expenses were her other major spending category in the fourth quarter, including a $100,000 retainer with Kinsaker Security Group, LLC, and $77,000 spent on a security vehicle.

But the Arizona senator’s campaign notably spent very little on payroll, with just over $7,700 paid in total to four staffers. That suggests Sinema has not started to staff up like a major Senate campaign would likely need to in an election year.

The filing deadline in Arizona is April 8, and Sinema would face an onerous requirement of some 40,000 signatures to secure a place on the ballot.