How to read Sen. Kyrsten Sinema quitting the Democratic Party


Political earthquake or campaign theatrics? How to read Sen. Kyrsten Sinema quitting the Democratic Party.

The midterms are over, but the politics of the 118th Congress are not exactly settled after Sen. Kyrsten Sinema of Arizona announced she was leaving the Democratic Party.

Whether this is in fact a political earthquake or simply a branding exercise for a 2024 Senate candidate, however, remains to be seen. Sinema didn’t cross the aisle, and so there might not be any actual changes to the way Congress functions. It’s a far cry from Jim Jeffords’ 2001 switch to the Democratic Party, which flipped the Senate and made Tom Daschle majority leader.

It’s also not totally clear how much her decision will change the 2024 Senate race. Sinema had ramped up the conflict with her party and was on track to drawing a strong Democratic primary opponent. Had she lost that primary, Arizona election law would have prevented her from running as a write-in in the general election. Now, however, as an independent candidate, she has a firm place on the November 2024 ballot.

What does it mean for the next Congress?

The biggest question was whether Democrats would have to behave as if they were back to a 50-50 Senate, after Sen. Raphael Warnock’s victory in Georgia gave Democrats a 51st vote. But multiple news outlets have reported that Democrats will continue to function as if it’s a 51-49 Senate, meaning Democrats will keep their edge in the composition of Senate committees. Sinema also said nothing would change about her work in Congress, indicating she would function more like Sens. Bernie Sanders or Angus King — two independent senators who caucus with Democrats, who we count as part of those 51 Democratic senators despite their official party status.


Sinema’s voting record strongly aligns with Democratic leadership’s priorities. She was a leading figure in negotiating 2021′s major infrastructure bill, communicating with President Joe Biden often over the course of months to successfully draft a $1 trillion deal.

But she has also broken from Democrats at key moments, like when the party was negotiating Biden’s signature social policy and climate agenda.

Sinema opposed raising corporate or income tax rates in order to pass a bill, putting her in the middle of negotiations over Democrats’ climate agenda — and stalling progress. Ultimately, Democrats agreed to drop a proposal to increase taxes by closing the so-called carried interest loophole that benefits financial executives in order to garner Sinema’s support. Sinema voted for the bill, known as the Inflation Reduction Act.

If Sinema does continue to stick with Democrats, then her switch practically doesn’t change much. She was a thorn in leadership’s side on some major issues in the past, and she’ll continue to be so in the 118th Congress.

The question is whether Sinema’s decision is an initial move toward more conservative positions or whether it’s simply a change of label to dodge a competitive primary.


First, King and Sanders face very little pressure to cross party lines, representing blue states. If those two senators face pressure for being too loyal to Democrats, it’s because their electorate doesn’t find mainstream Democrats to be progressive enough. That’s far from the case in Arizona.

Sinema could follow an example similar to that of Joe Lieberman, who decided to run as an independent Democrat after losing the Democratic nomination in 2006. For Lieberman, that switch was part of a broader shift toward conservative politics.

Then there’s the example of Sen. Lisa Murkowski of Alaska, who, to be clear, is not an independent. She’s a Republican. But after she lost her primary in 2010, she won a write-in campaign. That’s allowed her a level of independence from leadership of both parties that’s unparalleled in the current hyperpartisan political environment. She managed to win reelection despite facing a Trump-backed opponent in 2022 as well.

Facing little pressure from Minority Leader Mitch McConnell (R-Ky.), Murkowski still votes with Republicans a majority of the time — though the exceptions have been major, including voting against confirming Brett Kavanaugh to the Supreme Court and voting in favor of impeaching President Donald Trump in 2020.

What does this mean for 2024?

There’s been a clear formula for successful Democrats in Arizona’s statewide races: consolidate Democratic votes, win a majority of moderates and sprinkle in a few conservatives as a cherry on top.

That formula is now out the window for the 2024 Senate race.

Arizona had been showing subtle signs of shifting toward Democrats, a result of demographic changes in the state, before Trump ran for president. The state has a young Latino population that is becoming old enough to vote, and the relatively cheap real estate is drawing in a lot of Californians. But by villainizing John McCain, Trump hit the gas on the state’s political transformation.

Still, Sinema’s victory in 2018 delivered an electric shock to the entire political map, turning Arizona purple faster than anyone in the pre-Trump era could have imagined. Her victory presaged that of Democratic Sen. Mark Kelly’s and Governor-elect Katie Hobbs.

Ever since, the Arizona electorate has been in flux. Longtime Republicans, including the widow of McCain, found themselves supporting Democrats like Biden. And the new generation of Trump-aligned Republicans have largely allowed those voters to leave their party, continuing to go after McCain and his family. Kelly and Hobbs handily won independents and moderates in 2022.

By switching her party affiliation, Sinema might be endearing herself to those voters. But the first step for all those successful Democratic candidates was consolidating members of their own party. The chances that Democrats would consolidate behind Sinema before she switched parties were already slim. Now, they’re even slimmer.


Who would challenge Sinema in 2024?

Ruben Gallego has been considering a primary to Sinema for months, taking issue in particular with her unwillingness to vote for filibuster reform. Sinema’s exit from the Democratic Party might encourage other Democrats to consider a run for the Senate too. But for now, Gallego has the lane to himself, setting up a general election between an independent candidate, a Democratic nominee and an as-yet-unknown Republican nominee.

If Gallego does end up with a Democratic challenger, it’s possible that he shifts his attention from Sinema to his own primary, which could be a huge benefit for Sinema. In 2018, while the Republican primary stretched into August, Sinema never faced real opposition in her own primary. She avoided attacks for the majority of the cycle, occasionally airing ads that showed her playfully feuding with her brother or explaining why “we can work together.”

That brings a whole bunch of questions to the table. Does the Democratic Senatorial Campaign Committee stand by Sinema after supporting her in 2018? Despite the vitriol she faces from members of her own party, Sinema has a solid Democratic voting record.

And how does she engage with the 2024 presidential campaign, assuming Biden runs for reelection? Biden endorsed her in 2018 and headlined a fundraiser for her. Initial reports indicate that the Biden administration had been alerted before Sinema announced her decision to leave the Democratic Party and didn’t try to convince her to stay. Was that a sign of an amicable relationship or abandonment of a party nuisance?

Some of the calculus for Sinema will be out of Democrats’ hands. If Republicans nominate another Trump-endorsed figure like Blake Masters, who essentially gave McCain Republicans permission to vote for Democrats, Sinema could end up with more Republican and moderate voters than previous successful Democratic candidates running for statewide office.


The question for Arizona Democrats ever since Trump’s election has been whether they could win enough Republicans and independents to win. So far, they’ve had a stellar track record. Sinema seems to be going after those same voters — but she might be neglecting a key part of the electorate: Democrats.

Thanks to Lillian Barkley for copy editing this article.

  • Leah Askarinam
    Leah Askarinam

    Senior Editor

    Leah Askarinam is Senior Editor at Grid, overseeing coverage of politics, misinformation and the economy.

  • Maggie Severns
    Maggie Severns

    Domestic Policy Reporter

    Maggie Severns is a policy reporter for Grid covering complex policy stories and major headlines.