Here’s how the math in Arizona complicates Democrats' Senate path

Despite being outnumbered, Arizona Democrats have had a doable — but by no means easy — path to winning statewide contests over the last three election cycles. 

Carry almost all the votes from Democratic voters, win a majority of independents and woo an important sliver of Republicans.

It’s the formula that’s resulted in wins by Kyrsten Sinema (in 2018), President Joe Biden and Mark Kelly (in 2020) and Kelly and Katie Hobbs (in 2022). 

Arizona Senator Kyrsten Sinema announces departure from Democratic party

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But that equation might be much more difficult now with Sinema leaving the Democratic Party and registering as an independent, and with Rep. Ruben Gallego, D-Ariz., clearly eyeing the seat. 

Given that registered Republicans and independents both outnumber Democrats in the state, can either Sinema or Gallego (or any other Democrat) defeat a Republican nominee in a three-person race in 2024?

The math presents a pretty clear obstacle, as recent cycles show.

In 2018’s Arizona Senate race:

• 27% of all voters identified as Democrats, and Sinema won them, 97%-0%, according to the NBC News exit poll.
• Another 38% were Republicans, and Republican Martha McSally won them, 86%-12%.
• And 31% of voters were independents, and Sinema won them, 50%-47%. 

In 2020’s presidential contest in Arizona:

• 26% of voters were Democrats (Biden won them 96%-3%).
• 35% were Republicans (Donald Trump won them 90%-9%).
• And 39% were independents (Biden won them 53%-44%), per the NBC News exit poll. 

And in last November’s Senate race:

• 27% were Democrats (Kelly won them 97%-2%).
• 33% were Republicans (Republican Blake Masters won them 89%-9%).
• And 40% were independents (Kelly won them 55%-39%), according to the NBC News exit poll. 

Bottom line: Arizona Democrats have benefitted from an alliance with independents and even some GOP voters to beat Trump-backed Republican candidates in Arizona. 

(Importantly, neither Sinema nor Kelly faced real primary opposition in their successful bids, which allowed them to hug the middle of the electorate.). 

But with Sinema switching to an independent and with Democrats likely to run their own nominee, that alliance could unravel. 

And Democrats would find themselves at a disadvantage in a state where they’re outnumbered.