Arizona Democratic Rep. Ruben Gallego recently outraised Independent Sen. Kyrsten Sinema in what could be the most unpredictable Senate race of 2024

• Arizona Democrat Ruben Gallego outraised Independent Kyrsten Sinema in the first quarter of 2023.
• Gallego's campaign reported raising $3.74 million, while Sinema raised $2.1 million, per the FEC.

Independent Sen. Kyrsten Sinema of Arizona has not yet announced whether she'll run for reelection to a second term next year, but one of her potential Democratic opponents has already outraised her in first quarter fundraising.

Democratic Rep. Ruben Gallego, a Phoenix-area lawmaker who launched his Senate campaign in January, raised $3.74 million in the first quarter of 2023, which ended on March 31, per Federal Election Commission filings.

Gallego, who has been highly critical of Sinema's record in the Senate as it relates to support for President Joe Biden's agenda, reported that he had $2.7 million cash on hand.

Sinema's campaign reported raising $2.1 million in the first quarter, but she still retains a significant financial advantage overall, with nearly $10 million cash on hand, per the FEC.

Sinema, who was elected to the Senate in 2018 as a Democrat in a tough race against then-Republican Rep. Martha McSally, became an Independent last December, but she still retains her committee assignments from her former party and by and large has not dramatically changed her voting record.

While Sinema was generally a reliable supporter of Biden's Cabinet appointees and judicial nominees, she has been a wild card on major legislation and, alongside Democratic Sen. Joe Manchin of West Virginia, bore much of the brunt of liberal dissatisfaction over the pair's refusal to eliminate the legislative filibuster to pass sweeping voting-rights legislation.

Sinema's entry into the race would likely produce one of the most fascinating races in the country, as liberals and moderates dissatisfied with Sinema might opt for Gallego instead, while she could potentially siphon off Independents and moderates who still support her but otherwise would have backed Gallego.

Meanwhile, Republicans could either field a conservative with appeal in a general election or a polarizing candidate who is attractive to base voters but less electable among suburban moderates.

Pinal County Sheriff Mark Lamb entered the race for the GOP nomination earlier this month.

Other potential Republicans who could jump into the race include 2022 gubernatorial nominee Kari Lake, 2022 Senate nominee Blake Masters, attorney and businesswoman Karrin Taylor Robson, and former solar energy executive Jim Lamon.

The outcome of a competitive three-way Arizona race could very well determine control of the Senate.

And the race would also be held with the concurrent presidential election, which could feature a rematch between President Joe Biden and former President Donald Trump.

In 2020, Biden narrowly won Arizona, flipping a state that before that year hadn't gone for a Democratic presidential candidate since 1996.