Sen. Kyrsten Sinema (Ariz.) had plenty of reason to leave the Democratic Party and become an Independent, Senate Democratic aides and strategists say.

Her relationship with Democrats in her home state had deteriorated so badly she may not have survived a primary challenge in 2024. 

And the timing — while her Senate colleagues were still celebrating their victory in the Georgia runoff and the prospect of controlling 51 Senate seats — wasn’t a shock either, Democratic sources said Friday. 

After all, she had upstaged fellow Democrats several times in the past two years. 

“I’m not surprised and I think that would likely be the same answer by anyone who really knows Sen. Sinema,” John LaBombard, a former senior adviser to Sinema, said. “I think it’s a really good move for her in terms of her ability to keep working on these big bipartisan deals.“ 

Sinema often grabbed the spotlight after Democrats captured the Senate in 2021, sometimes by blocking key elements of President Biden’s agenda, such as his plan to raise the corporate tax rate, and other times by taking leading roles in negotiating infrastructure and gun violence legislation that gave Biden some of his biggest legislative victories.  

She told CNN in an interview that removing herself from “the partisan structure” was “true to who I am and how I operate” and would “provide a place of belonging for many folks across [her] state and the country, who are also tired of partisanship.”  

LaBombard, who now serves as a senior vice president at Rokk Solutions, a bipartisan public affairs firm, said the change in party affiliation reflects how Sinema has been operating in the Senate over the past two years as a centrist dealmaker. 

He said it could “reset” expectations of how she will vote, which could ease some of the tensions that built up between Sinema and Democrats when she broke with them on tax policy and Senate rules reform.  

“There’s some part of this I think could really serve as a helpful reset in expectations in the Democratic Party and Congress as a whole, and a good reminder that diversity of thought and opinion is okay,” he said. “Both parties for long-term success should really think hard about the kind of expectations they put on their more independent-minded members.” 

“This might be a release valve of pressure,” he added.  

Sinema doesn’t plan to caucus with either party in the Senate, but Senate Majority Leader Charles Schumer (D-N.Y.) announced Friday that he will let her keep her committee assignments.  

“She asked me to keep her committee assignments and I agreed. Kyrsten is independent; that’s how she’s always been,” he said in a statement.  

The practical effect will be that not much will change for Sinema in her day-to-day Senate life.  

She hardly ever attended Senate Democratic caucus meetings even before she announced she would become an independent. And she’ll still working with bipartisan “gangs” outside of the committee structure 

Senate Democrats say they will still hold one-seat majorities on the committees in 2023 and 2024, which means they could issue subpoenas and discharge bills and other business out of committee without Republican votes.  

The White House issued a statement Friday pledging Sinema as “a key partner on some of the historic legislation President Biden has championed over the last 20 months” and pledging “we have every reason to expect that we will continue to work successfully with her.”  

The biggest practical implication of becoming an independent is that Sinema will not have to face a Democratic primary challenger in 2024 if she runs again. 

As a result, she won’t have to defend her opposition to key elements Biden’s tax agenda or her opposition to changing the Senate’s filibuster rule to allow voting rights legislation to circumvent GOP opposition.  

“She wasn’t going to debate partisan purism,” said Stacy Pearson, an Arizona-based Democratic strategist.  

Sinema has not discussed her plans for 2024, and party strategists are split on how much tougher her path to reelection would be as an Independent. 

Pearson said Sinema’s announcement wasn’t a big surprise given how rocky her relationship had become with the state Democratic Party, which censured the senator after she refused to change the Senate’s filibuster rule in January.  

“I am not surprised she has formalized her separation from the Democratic Party, which has already censured her and continues to criticize her about the negotiations she makes in the state’s interests,” Pearson said.

Arizona Democratic Party Chairwoman Raquel Terán issued a scorching response to Sinema’s announcement, declaring the senator had “fallen dramatically short” as a leader.  

“Sen. Sinema may now be registered as an independent but she has shown she answers to corporations and billionaires, not Arizonans. Sen. Sinema’s party registration means nothing if she continues to not listen to her constituents,” she said.  

The state party’s executive board announced in January that it had decided to formally censure the senator over what it characterized as “her failure to do whatever it takes to ensure the health of our democracy.”  

Sinema made it clear in her Arizona Republic op-ed that she was sick of getting that kind of criticism for working across the aisle and trying to preserve the Senate’s tradition of bipartisanship.  

“Pressures in both parties pull leaders to the edges, allowing the loudest, most extreme voices to determine their respective parties’ priorities and expecting the rest of us to fall in line,” she wrote. “In catering to the fringes, neither party has demonstrated much tolerance for diversity of thought.”  

Former Sen. Ben Nelson (D-Neb.), who worked as a bipartisan dealmaker in the Senate during President Obama’s first two years in office in 2009 and 2010, said that an officeholder’s relationship with the state party is a key factor in determining national party allegiance.  

“That’s like going home and having your family dog bite you,” he said. “I never encountered that.”  

Nelson said that occasionally the “somebody from the really, really far-left” would run a television ad against him, but the polling always showed he had “overwhelming support” from Democrats in Nebraska.  

Dan Pfeiffer, a former senior Obama adviser, on Friday speculated that Sinema didn’t think she could win a primary and by registering an Independent may put pressure on Democrats to support her out of fear that Sinema and a Democrat splitting the vote would hand the seat to Republicans.

“The Sinema thing is very simple. Her calculus is that 1) She can’t win a primary; 2) If she runs as an independent who caucuses with the Dems, another Democrat can’t run bc they would split the vote and give the seat to Republicans,” he tweeted.  

But other Democratic strategists predict that Arizona Democrats will certainly run a candidate against Sinema in 2024, if she chooses to run for reelection, and predict the primary for the nomination could be crowded.  

Rep. Ruben Gallego (D-Ariz.) is viewed as a likely Senate candidate in the next election cycle and wasted no time in taking a shot at Sinema on Friday.  

“We need senators who will put Arizonans ahead of big drug companies and Wall Street bankers,” he said in a statement.  

Pearson, the Arizona-based political strategist, said Sinema would still have a good chance of winning reelection in a three-way general election race, noting that independents make up about a third of registered voters in the state.  

She said the Democratic primary could be very crowded and very competitive, meaning that whoever emerges with the nominee could be battered heading into the general election.  

“Democrats in Arizona only comprise 30 percent of the electorate. It’s the smallest bloc behind Republicans on top and independents in second place. So when she talks about representing Arizona, she’s not lying. This isn’t hyperbole,” she said.