Arizona Rep. Ruben Gallego claimed that Senator Kyrsten Sinema left the Democratic Party because she was worried about facing him in a primary.
Gallego, considered a progressive politician, said she decided to become an independent because she will have an 'easier time' running for reelection in 2024.
'She can't win a primary against me and this is her only option,' Gallego said in an interview with MSNBC host Chris Hayes on Monday.
Gallego has not launched an official bid for the Senate as it's still a bit early to wade into the 2024 election waters – but he expressed public interest in the upper chamber and left-wing organizations have encouraged him to run for Sinema's seat.
Independent Vermont Senator Bernie Sanders suggested over the weekend that he would support a progressive challenger against Sinema.
Representative Ruben Gallego said he is the reason Kyrsten Sinema left the Democratic Party, claiming that she was afraid to face him in Arizona's 2024 primary election. Gallego has repeatedly suggested he will make a bid for the upper chamber next election
'Right now, if you had to choose, would you run for Senate?' Hayes asked Gallego.
'Well, right now, what I'm choosing to do is to put the team together so I can make the decision,' he said. 'I've been putting together a great team, I think, that will help me get in the right direction. I am a Marine first, a congressman second, and Marines [are] prepared. That's what I'm doing right now.'
Sinema has long been considered one of the most moderate Democrats in the Senate until she officially changed party affiliation to independent last week. Republicans and Democrats say the move will do little to 'functionally' change the upper chamber since she will still caucus with Democrats.
When asked if he was surprised that Sinema left the Democratic Party, Gallego told MSNBC: 'Not really, I thought she was going to do this eventually. Look, she claims to be independent. That's not the case.'
Critics of Sinema claim that she has 'sabotaged' progressive legislation over the last two years.
Sinema told CNN's Jake Tapper when talking about her party switch: 'I've never fit neatly into any party box. I've never really tried. I don't want to.'
'Removing myself from the partisan structure – not only is it true to who I am and how I operate, I also think it'll provide a place of belonging for many folks across the state and the country, who also are tired of the partisanship,' she added.
Sinema's switch isn't unusual in a state where registered independent voters outnumber Democratic voters.
Historically moderate Senator Kyrsten Sinema announced last week she was leaving the Democratic Party to officially become an independent
Most of Arizona's registered voters are Republicans, making up 34.67 percent of the voting bloc in the southern border state. But in a close second are independent voters with 33.89 percent. Democrats are in third, making up 30.66 percent of voters in Arizona.
Despite the battleground state leaning red, it swung blue in the 2020 presidential election as 0.4 percent more voters cast their ballot for Joe Biden over Donald Trump. Arizona voted red in 2016 by a 3.5 percent margin, helping propel Trump to the White House with their 11 Electoral College votes.
The state has shown an increasingly blue-lean, especially in the 2022 midterms, which saw voters choose to replace outgoing GOP Governor Doug Ducey with Democrat Katie Hobbs over her pro-Trump challenger Kari Lake.
Democratic Senator Mark Kelly also held onto his Senate seat in the midterm elections against Republican challenger Blake Masters.
Gallego accused Sinema of no longer representing her Arizona constituents, and said he hasn't spoken to the senator recently.