Arizona Senator Kyrsten Sinema has changed her party affiliation from independent to Arizona Democrats, which is a major blow to Washington’s narrow majority of Democrats.

The first-term senator said in a 45-minute interview that she would not join the caucus of Republicans. She also stated that she plans to vote the same way as she did for four years in Senate. She stated that “nothing will change my values or my behaviour.”

If Sinema keeps her word, Democrats will still have a viable Senate majority in the next Congress. However, it won’t be as neat and tidy as the 51 seats they took. They are expected to have the votes necessary to control Senate committees. Sinema’s decision means that Sen. Joe Manchin (D.W.Va.), a pivotal swing voter in the 50-50 chamber for the past two years, will retain some but not all his enormous influence in the Democratic caucus.

Sinema refused to answer whether she would run for reelection 2024. She informed Chuck Schumer, Senate Majority Leader, of her decision on Thursday.

Sinema stated that she doesn’t expect that much will change in the Senate structure. I am an independent.

She stated that her decision to leave Democratic Party was a result of her “never really fitting into any box of any party” — something she also said about her fiercely independent state, and the millions of unaffiliated voters in the country.

Sinema is a well-known iconoclastic. She is an Ironman triathlete, moonlights at Napa Valley wineries and hangs out with the GOP side of the aisle during the floor vote.

According to the 46-year old, her party switch is a natural next step in a career that has been built on working as closely as possible with Republicans and Democrats. This approach allowed her to play a key role in bipartisan agreements on infrastructure, gun safety, and same-sex marital rights during the current 50-50 Senate. Some Democrats are also furious at her resistance to higher taxes and attempts to weaken filibuster.

Her decision will be a resounding success for her GOP allies, and it is sure to inspire her Democratic critics on the Hill and at home. Sinema stated that criticism from outside entities “doesn’t really matter” and that she will run for a hard race after her announcement becomes public. “That’s mostly what my Friday mornings consist of.”

Before her party switch, there were rumblings that she would be facing a primary challenge from Ruben Gallego (D-Ariz.) in 2024. If she runs for reelection, becoming an independent will prevent her from facing a head-to–head primary against Gallego (or another progressive). If both Democrats and Republicans are against her, a general-election campaign could become chaotic.

Sinema stated that she has a different goal: to completely separate herself from the Democratic Party, despite its support in her 2018 hard-fought race. She defeated former Senator Martha McSally (R.Ariz.) in the Arizona Senate race. This was her first win as a Democrat in over 30 years.

Sinema would not entertain the idea of seeking a second term in the Senate: “It is fair to say I’m not talking right now about it.”

“I keep my eyes on what’s happening right now. It’s right for me to register as an independent. It’s right. It’s right for me.” She said that she believes it is.

She did however dismiss one possibility her independent status might raise: “I’m not running for president.”

It has been a decade since Senate party switching — when former Pennsylvania Senator Arlen Specter joined the GOP to become a Democrat — but even longer since former Senator Joe Lieberman went from Democrat to Independent. Manchin regularly denies rumors that he is leaving the Democratic Party.

Sinema stated that she is not lobbying anyone directly to leave either the Democratic Caucus of the GOP Conference. She said that she would like the Senate foster “an environment where people are comfortable and confident saying what they believe”

Practically, this means that she will continue to work with the Senate’s loose group bipartisan dealmakers. Some of them are retiring this year. She has already spoken to Sen.-elect Katie Britt, R-Ala. about how they can work together.

She maintains a close relationship with Kevin McCarthy, House Minority Leader. This could be a benefit to a GOP House or a Democratic Senate. McCarthy said that she and she have been friends for many years.

She insists that she will not change her previous approach to confirming Democratic presidential nominees. She said she still supports them but scrutinizes them and expects to keep her assignments through the Democrats. She also said that nothing will change in her ideology, which she described as more liberal on issues like abortion than most Republicans and more conservative than most Democrats.

Sinema voted for the conviction of former President Donald Trump in his two impeachment trial. She opposed Trump-backed Supreme Court Justice Amy Coney Barrett, and supported Supreme Court Justice Ketanji brown Jackson, who was tapped by President Joe Biden. She supported two Democratic party-line legislations this Congress: one on coronavirus assistance and another devoted to climate change, prescription drugs, and taxes.

She stated that she has good relations with Biden, the Senate majority leader, and Minority Leader Mitch McConnell. McConnell invited her to give an closely-watched speech about bipartisanship in her home state several months back.

Unlike independent Sens. Sinema will not attend weekly Democratic Caucus meetings (Vt. and Maine), but she does it very rarely now. She isn’t certain if her desk will be on the Democratic side.

Sinema, who was elected to three terms as a member of the House and a state legislator prior to her Senate election, said that she was “delighted” by Sen. Raphael Warnock (D-Ga.’s) Tuesday reelection win. Although Warnock’s victory will likely take some of the sting out of her decision, Sinema stated that she wasn’t waiting for the Georgia runoff election results, which seemed to give her a party with a majority for the first-time since 2014.

She said that her announcement was “less about timing” than she had thought. It’s about me asking how I can be the most productive. How can I stay true to my core values and the values of Arizona? And how can I keep being an independent, productive voice for Arizona?

She doesn’t want to be involved in the calculation of how many seats they have now.