(CNN) Sen. Kyrsten Sinema's surprise decision to become an independent has Democratic leaders struggling to answer a basic question: How should they deal with her if she runs for reelection in Arizona?
In interviews with top party leaders and rank-and-file members on Monday, Democrats were sidestepping the sensitive question and handling the politically fraught situation delicately, knowing that a misstep could backfire and have serious ramifications for their party.
"When they call me for advice, I'll give it in confidence," said Senate Majority Whip Dick Durbin, the chamber's No. 2 Democrat, told CNN when asked if party leaders should stay out of the race.
Durbin added: "I plan to stay out of Arizona politics."
If Sinema runs for a second term but party leaders put their muscle behind a Democratic candidate instead, the electorate could splinter in the purple state and help Republicans win back a critical seat. Plus, backing a Democrat in the race could risk alienating Sinema whose decision to continue to align with her former party on her committee assignments essentially solidifies their 51-49 majority.
But if they get behind Sinema or stay neutral in the race, as they've done with other independents who caucus with them, they would infuriate progressives eager to knock off the moderate Sinema over her refusal to gut the Senate filibuster and approve many of their priorities over the last two years.
And no matter how they handle the mercurial senator, they could be left with a messy, three-way race in 2024 at a time when they will be battling to defend 23 seats compared to 11 for the GOP -- all of which has caused anxiety in the Democratic ranks.
For now, Senate Majority Leader Chuck Schumer and his top deputies said they are in a wait-and-see mode, planning to see how the field forms and whether Sinema will indeed run as an independent in the 2024 cycle. Then, they said, they will begin to make some critical decisions.
"When she says she's gonna run, you come back to me," Sen. Patty Murray, a Democrat from Washington state and a member of her party's leadership, told reporters.
But already, the field appears to be taking shape.
Rep. Ruben Gallego, a member of the Arizona House delegation, told CNN that "We're already putting the team together," and he'd make a decision about a run sometime next year. He said he would soon reach out to Schumer and the Democratic Senatorial Campaign Committee -- and he dismissed the possibility that Sinema could win as a third-party candidate or that a Republican could pull off a victory in a three-way race. He contended that a Sinema candidacy "assures a Democrat wins."
"They could do what they want," Gallego said when asked about party leaders' decision on how to handle the race. "But it's going be a waste of money to try to prop up a third-party candidate because it's just not going to happen. Not in Arizona."
But Gallego could have a challenge in the primary -- potentially from Democratic Rep. Greg Stanton, who won reelection in his swing district in the fall.
Stanton told CNN on Monday he is "taking a serious look" at the race.
"My focus until recently has been winning my 2022 frontline reelection," Stanton said. "Sen. Sinema's recent decision to leave the Democratic Party has no bearing on my thinking."
But it's a decision that has Republicans and Democrats alike weighing what comes next.
Sen. Gary Peters, the current chairman of the Democratic Senatorial Campaign Committee, plans to step aside from that post in the 2024 cycle, and no new senator has announced plans to take that position as of yet.
"At this moment, I'm really happy to say that's the job of the next DSCC chair to make that determination," the Michigan Democrat said when asked how the party committee should handle an independent run, given that it typically backs Democratic incumbents.
Sinema, who has a sizable war chest with nearly $8 million in cash, has not tipped her hand about whether she will run again, though many suspect she left the party in order to spare herself a grueling primary fight in 2024.
"I'm just not worried about folks who may not like this approach," Sinema told CNN on Thursday. "What I am worried about is continuing to do what's right for my state. And there are folks who certainly don't like my approach, we hear about it a lot. But the proof is in the pudding."
On Monday, Sinema made a brief appearance on the Senate floor, casting a vote for a Biden judicial nominee before she headed out and ignored reporters' questions.
But in the halls of the Capitol, the two sides were assessing how her move could scramble the 2024 map.
"It's going to be a competitive state in 2024," said Sen. Steve Daines, a Montana Republican who will chair the National Republican Senatorial Committee in the coming cycle.
Republicans are hopeful that the progressive push to oust Sinema will only bolster their chances to take the seat.
Indeed, Sen. Bernie Sanders, a Vermont independent, attacked Sinema as a "corporate Democrat" who "helped sabotage" the Biden agenda.
On Monday, he wouldn't say if he believes Democratic leaders should try to knock her off in 2024.
"I think that decision rests with the people of Arizona," Sanders said Monday.
A like-minded liberal, Sen. Elizabeth Warren of Massachusetts, also punted on the question.
"I am just not focused on that," Warren said. "I am focused on what we need to do in the next two weeks. That's my responsibility."
For the last two years, Sinema has been a complicated and polarizing figure for Democrats. The newly independent senator has helped clinch victories for the Biden administration on a major infrastructure package, prescription drug pricing, same-sex marriage legislation and the first gun violence law in a generation. But she also rebuffed Democratic efforts to raise tax rates on corporations and individuals -- and she, along with Sen. Joe Manchin of West Virginia, stood their ground against Democratic efforts to gut the filibuster and pass a voting rights bill, saying the 60-vote threshold is essential to preserving the rights of the minority to shape legislation.
Like Sinema, party leaders are now watching Manchin closely as he weighs whether to run in 2024. On Monday, he would not ruling out joining Sinema and spurning his Democratic Party label and becoming an independent.
"I'll look at all of these things," Manchin told CNN. "I've always looked at all those things, but I have no intention of doing anything right now. Whether I do something later, I can't tell you what the future is going to bring."
In private meetings, Schumer has been careful not to criticize Sinema, according to senators who have spoken to him. In the White House and Schumer statements Friday, both praised Sinema's record in the Senate and made clear they'd continue to work with her. It's a message several senior Democrats also echoed on Monday.
Sen. Debbie Stabenow of Michigan, a member of party leadership, said she and Sinema have worked together on mental health provisions central to the gun legislation, among other issues.
And when asked if she will get behind Sinema, Stabenow wouldn't say.
"That's something that that you know I'm sure will be talked about down the road."
"That's a call for somebody else," Sen. Jon Tester, a Montana Democrat, added when asked about the party backing Sinema in 2024.
Even Sen. Mark Kelly, the newly reelected Arizona Democrat, steered clear of the sensitive topic on Monday.
"I worked very closely with Sen. Sinema -- two years now to get stuff done," Kelly said. "The DSCC, and what that they do over there, is outside my area of expertise."
Kelly would not say he would support her if she ran.