A memo from Sen. Kyrsten Sinema’s political team is the latest signal the Arizona Independent is planning a reelection bid, teeing up an extraordinary three-way race in a critical swing state.

Although Sinema has not confirmed her plans, a prospectus obtained by NBC News indicated she’s gearing up for a potential run and outlined the shares of partisan voting blocs her political team believed she could garner.

But strategists in the Grand Canyon State believe Sinema faces a difficult path to victory, underscoring the unpredictability of what will be one of the most closely watched races next year as Democrats look to hold onto their majority.

“I think Sen. Sinema is really going to put to the test that age-old mantra that voters want to elect people who will work across the political aisle to get things done,” said Republican strategist Barrett Marson.

Democrats and Republicans alike are bracing for a high-stakes Senate race in Arizona next fall that will prove critical for either party’s hopes of capturing the majority in the upper chamber. Rep. Ruben Gallego (D-Ariz.) has announced a run on the Democratic side while Pinal County Sheriff Mark Lamb is running on the GOP side.

Former gubernatorial candidate Kari Lake (R) is “likely to make a final decision in October” on whether she runs in the Senate race, her senior adviser Caroline Wren told The Hill last week. However, Lake is largely expected to announce a bid, and strategists believe she will easily clinch the GOP nomination. 

But Sinema, who late last year changed her partisan affiliation from Democrat to independent, has largely stayed mum on her plans. The prospectus from her campaign suggests, however, she’s seriously considering reelection with a pathway that would include 60 percent to 70 percent of independent voters, 25 percent to 35 percent of Republican voters and 10 percent to 20 percent of Democratic voters, according to NBC News. 

Pollsters in the state say those numbers could be feasible for the senator, but executing that goal will be tricky. 

“The prospectus is saying the same thing that we have been saying since she jumped the D ship last December. Our belief was 20% D, 25-30% R and 60+ Unaffiliated. That comes out to roughly 43% in a general, which should be enough to win,” Republican strategist and pollster Chuck Coughlin said in an email.

“What is unsaid there, is how difficult it is. She has no partisan base and unaffiliated voters tend to be all over the place and largely remain [undecided] until late. Both of those partisan numbers will be difficult to reach,” he continued. “Very difficult campaign, but possible.”

Coughlin estimated that such an approach would require a “highly expensive, highly aggressive messaging campaign” — potentially spending as much as $20 million during the cycle — to target largely independent voters while also defending herself against attacks from Lamb and Gallego.

But experts are warning not to count out Sinema this early in the primary.

“Prior to Kyrsten Sinema, Democrats couldn’t win for the life of them statewide in Arizona, and she literally wrote the playbook and she always seems to be a little bit two steps ahead,” pollster Mike Noble said.

Still, polling so far in the primary, while early, suggests Gallego fares well in several potential three-way matchups. 

In polling from Noble Predictive Insights conducted in mid-July, a hypothetical three-way match between Gallego, Lake and Sinema found Gallego leading all three candidates at 34 percent, 25 percent and 26 percent, respectively. But a separate 15 percent said they were undecided. 

A separate one conducted in early August by Emerson College Polling found Gallego leading Lamb and Sinema in another hypothetical three-way race, with the Arizona Democrat receiving 36 percent, Lamb at 29 percent and Sinema at 21 percent. A separate 15 percent were undecided. 

“Only one person is traveling the state and talking directly to Arizonans about creating good paying jobs, cutting the cost of prescription drugs, and taking care of our veterans, and that’s Ruben Gallego,” Gallego campaign spokeswoman Hannah Goss said in a statement. 

“He’s laser focused on fighting for everyday Arizonans — and that’s why he’s going to win this race, just as the data suggests,” she added. 

Rick Gorka, a communications adviser for Lamb, slammed Sinema in his statement as “ineffective” and argued she was “trying to have her cake and eat it too.”

“… She has enabled the Biden administration’s abhorrent failure on our border while Arizonans suffer with higher costs for food, gas, and other necessities. It is time for her to be sent packing,” he added.

Sinema’s campaign did not respond to requests for comment for this story. 

Some Democrats in the state are skeptical about Sinema’s pathway to reelection and have soured on her. Former Democratic media consultant David Doak called Sinema a “horrible” senator and said he was supporting Gallego in the general election if Sinema runs.

“I think one of the things that people dislike about her most is that it appears that compromise is her goal, rather than good results produced by compromise,” Doak said. 

Doak pointed to the issue of the filibuster, a procedural Senate rule that requires 60 senators to advance most pieces of legislation. Sinema and Sen. Joe Manchin (D-W.Va.) have drawn the ire of Democrats for refusing to entertain the idea of changing the filibuster in an effort to pass legislation on issues like voting rights.

Sinema has defended her stance on the filibuster, saying that the Senate procedural rule “protects the democracy of our nation rather than allowing our country to ricochet wildly every two to four years” — referring to the idea that legislation could be easily undone or changed when a Senate majority changes. 

But her stance has angered Democrats. 

“It’s like with the filibuster … We have to reach compromise, so therefore, you know, the filibuster is more important than voting rights,” Doak said. “Well, to a lot of people, that doesn’t make much sense.”

John LaBombard, a former aide to Sinema, suggested Gallego doesn’t fit the bill for the kind of Democrats who have been elected statewide in Arizona and argued that the prospectus’s projected targets are “eminently doable.”

Still, he acknowledged, a potential three-way race would be a “dogfight” and “highly unpredictable.”

As the 2024 races continue to ramp up, Sinema will face increasing scrutiny over a timeline for a potential reelection run. Though some like LaBombard believe she has some time before making an announcement, others say she might need to make a move soon. 

“If I’m in that universe, I’d be thinking about, ‘Hey, who am I going to hire to run my campaign since my Democratic base has left me? Who am I going to hire as a pollster because my Democratic base has left me? Who am I going to hire as a grassroots operative since my Democratic base has left me?'” said Coughlin, the Arizona-based pollster.

“I’d be wantin’ pretty quickly to put a team together that can functionally work with me to narrate my candidacy,” he added. “Cause we know, you know, the worst thing that can happen is having a candidate run their own campaign.”