The 2024 election is still a long way off, but several lawmakers have already announced they are running for one of the 34 Senate seats up for grabs. There are a few races in particular to keep an eye on, like Arizona’s, where Democrats and Republicans both aim to oust the state’s newly independent senator, Kyrsten Sinema. Here’s everything you need to know:

Could California soon have a new senator?

Sen. Dianne Feinstein (D) has not yet revealed whether she will seek re-election in 2024. In 2022, several Democratic lawmakers shared with The San Francisco Chronicle their concerns that Feinstein, who will turn 90 years old in June, is experiencing cognitive decline and is no longer fit to serve. When the report came out, it got people talking about possible candidates to replace Feinstein, who has represented California since 1992.

Rep. Katie Porter (D-Calif.), an attorney whose district is in Orange County, announced on Jan. 10 that she is running for Senate, telling the Los Angeles Times, “I think that people understand that Washington is broken, and they see it caters to billionaires, powerful corporations, and special interests, and in doing that leaves families behind and threatens our democracy. I’ve seen how this corruption threatens our country and our economy. I want to run to do what I have been doing in Congress — standing up to special interests and fighting for families.”

Porter, 49, said she spoke with Feinstein staffers ahead of her announcement, and has “deep respect” for the senator, adding, “I think she will make her own decision in her own time. That’s up to her. She is a trailblazer, and the path she created for women in California politics is one I am proud to follow.” Rose Kapolczynski, a Democratic strategist, told the Times it was a good move for Porter to become the first California Democrat to announce a Senate run. “There’s always an advantage in being early, as long as you’re not seen as inappropriately speculating on someone’s retirement,” she said.

She may have broken the dam, as she was soon joined by Rep. Adam Schiff (D-Calif.), who announced his candidacy on Jan. 26. In his announcement, Schiff said: “We’re in the fight of our lives—a fight I’m ready to lead as California’s next U.S. Senator.”

Rep. Barbara Lee (D-Calif.) also recently told colleagues she also plans to run for the seat. While Lee has not formed an official Senate committee, she did share her intention during a meeting of the Congressional Black Caucus, and received a standing ovation, the Times reports. Allies of Sen. Bernie Sanders (I-Vt.) have also been pushing Rep. Ro Khanna (D-Calif.) to enter the race, and he said he’ll make a decision sometime in the next few months. 

What’s happening in Arizona?

Her term is up in 2024, but Sen. Kyrsten Sinema of Arizona, who recently changed her party affiliation from Democrat to independent, has not shared whether she intends to run for re-election. There is one Arizona Democrat who hopes to take her seat: Rep. Ruben Gallego, who announced on Jan. 23 that he is running for Senate. “Growing up poor, all I had was the American dream,” Gallego, 43, tweeted. “It kept me going: as a kid sleeping on the floor, a student scrubbing toilets, a Marine losing brothers in Iraq. Today, too many Arizonans see their dream slipping away. I’m running for the U.S. Senate to win it back for you!”

Gallego, who has been in the House since 2014, is of Colombian and Mexican descent, and if elected, would become Arizona’s first Latino senator. Democrats have long been unhappy with Sinema’s defense of the filibuster and opposition to major parts of their agenda, but in a statement, Gallego said the “problem isn’t that Sen. Sinema abandoned the Democratic Party — it’s that she abandoned Arizona. She’s repeatedly broken her promises, and fought for the interests of Big Pharma and Wall Street at our expense.”

While no Republicans have officially entered the race yet, several are thinking about giving it a go. Kari Lake, the former television news anchor who lost the Arizona gubernatorial race in 2022, is contemplating throwing her hat in the ring, a person close to her told CNN. A spokesperson for Blake Masters, who was defeated in the 2022 Senate race by incumbent Sen. Mark Kelly (D), is also “strongly considering” running in 2024, his spokesperson shared with CNN. Karrin Taylor Robson lost the most recent GOP gubernatorial primary to Lake, and in a statement said she is “still deciding how I can best serve the state that I love.” She added that “many Arizonans” have contacted her about the Senate race, “hopeful that our party will nominate a strong, authentic conservative who will not snatch defeat from the jaws of victory.”

Who’s in the running in Indiana?

In December, Sen. Mike Braun (R) announced he will not be running for re-election, and will instead enter the Indiana gubernatorial race. Rep. Jim Banks (R-Ind.) became the first Republican to say they will run for Braun’s seat, telling The Associated Press on Jan. 17, “I just believe now more than ever that we need conservatives in the Senate who are going to fight back against radical Democrat policies instead of going along with it. Republican primary voters are looking for a conservative fighter, someone to go to Washington and fight for Hoosier family values and against the radical, socialist, and woke agenda that Democrats are pushing in Washington.”

Banks, 43, was first elected to Congress in 2016, and remains a staunch supporter of former President Donald Trump. There are two other Indiana Republicans who are contemplating running for the Senate seat: Rep. Victoria Spartz and former Gov. Mitch Daniels, now the president of Purdue University. Spartz told reporters in December she had been “asked to consider” running for Senate, but did not say who approached her. Daniels has not said anything publicly about running, but people close to him told ABC News he has not ruled out entering the race.