Just over two weeks into the new year and candidates are already preparing for the 2024 Senate race.

Thirty-four Senate seats will be up for grabs, 23 of which are currently occupied by Democrats and independents. Republicans can regain control of the chamber if they gain two seats or retake the presidency and pick up one seat.

In efforts to get ahead, candidates have already begun announcing their bids for Senate. In California, a handful of House reps may compete for the seat of an incumbent who is expected to retire. And in Missouri, a Marine Corps veteran aims to unseat a Republican who cheered on protesters outside the Capitol during the Jan. 6 insurrection.

Here's a look at some of the races that will shape the Senate in the 119th Congress.

Democratic representatives set to duke it out in California

At 89 years old, Democratic Sen. Dianne Feinstein is the oldest member of the 118th Congress. With 30 years of congressional experience under her belt, she's the state's longest-serving senator, as well as the nation's longest-serving female senator.

Though she has yet to announce her intentions, it is widely expected that she will retire, and four of the state's House members are already eyeing her seat.

Rep. Katie Porter represents Southern California's Orange County and serves on the House Oversight and Reform Committee, the Natural Resources Committee and is the vice chair of the Subcommittee on Government Operations.

Having just been elected to a third term, she launched her official bid for Senate on Tuesday, vowing over Twitter to "stand up to special interests, fight the dangerous imbalance in our economy, and hold so-called leaders like Mitch McConnell accountable for rigging our democracy."

The day after Porter announced her 2024 run, 25-year House veteran Rep. Barbara Lee told colleagues behind closed doors that she intends to run for the Senate as well, Politico reported. She told Politico that now is not the time to announce a run, with the state having recently battled major rainstorms and flooding, and out of respect for Feinstein.

Lee has represented the Oakland-portion of the San Francisco Bay Area since 1998 and currently serves as co-chair on the Policy and Steering Committee and is a member of the Budget and Appropriations Committees. She has long been a champion in the fight to end HIV/AIDS and is an advocate for combating poverty, helping to create the Out of Poverty Caucus in 2007.

Two other congressmen, Reps. Adam Schiff and Ro Khanna, are also rumored to be considering a 2024 Senate bid. Schiff told Fox News Los Angeles that he has gotten encouragement to run for Senate from the people of California and other politicians, but he is waiting to see what Feinstein's plans are.

"If Sen. Feinstein retires, then I will give it very serious consideration," Schiff said. "It's a great responsibility and in terms of continuing the work I've been doing to protect our democracy and fight for an economy that works for everyone, that would also give me a chance to try to meet those objectives for all Californians."

Multiple news outlets are reporting that Khanna, who represents Silicon Valley, is contemplating a run in 2024, but like Lee and Schiff, he has yet to make an official announcement.

Marine Corps veteran hopes to dethrone an incumbent in Missouri

Republican Sen. Josh Hawley came under intense scrutiny from Democrats and the House Select Committee to Investigate the January 6th Attack on the United States Capitol after video surfaced showing the congressman welcoming rioters outside the Capitol, holding his fist in the air in a sign of solidarity. Another clip showed Hawley shortly after, running from the same mob once they breached the building.

Having lost faith in Hawley, Democratic candidate and Marine Corps veteran Lucas Kunce has set his sights on the Senate.

"Our state deserves a Senator who will stand up and fight for it, not run for the exit like Josh Hawley," Kunce wrote on his campaign website. "I'm running for U.S. Senate to be the warrior for working people that Missouri deserves. To fight for our state. And we aren't fighting the corporate status quo just to make a point. This is a race we can win."

Kunce is banking on his real-world experience carrying him to victory: medical bills pushing his family into poverty as a kid; utilizing a Pell Grant to afford a higher education; and deployments to Iraq and Afghanistan as an officer in the Marines.

But 2024 won't be his first run for Senate. Kunce ran against Trudy Busch Valentine in the state's Democratic primary last year, ultimately losing by just under 18,000 votes. Valentine later lost in the general election to Republican Eric Schmitt.

Michigan's first female senator is stepping down, creating an opportunity for Republicans

After a storied career encompassing 16 years in the Michigan House of Representatives and Senate followed by 25 in the U.S. House and Senate, Democratic Sen. Debbie Stabenow announced last week that she will not seek reelection in 2024.

As the first woman from Michigan elected to the Senate, Stabenow believes it's important to step aside and make room for a new generation of lawmakers.

"I am proud that my accomplishments have made a difference in people's lives and created a strong foundation for a healthy and prosperous future for our state," she said in a statement.

According to WKAR, Democratic Rep. Elissa Slotkin is strongly considering a bid for the seat, though she has not formally announced her plans. She did indicate an interest in expanding the work she does in her district statewide.

"To do that at the state level certainly interests me, and so I'm taking a hard look at it, but it's not a simple decision," Slotkin told WKAR. "It's not easy. It shouldn't be taken lightly."

Democrats are not the only ones eyeing the seat though. Stabenow's retirement is an opportunity for Republicans, which could help them regain control of the Senate.

National Republican Senatorial Committee Communications Director Mike Berg said in a statement that the GOP will "aggressively target this seat in 2024. This could be the first of many Senate Democrats who decide to retire rather than lose."

Neither a Republican nor Democrat has yet to announce a run to fill Stabenow's seat.

A state senator in Ohio will take a second shot at U.S. Senate

Ohio state Sen. Matt Dolan ran for the U.S. Senate last year but lost in the primary against fellow Republican and now-Sen. J.D. Vance. Refusing to be dissuaded, Dolan announced Tuesday that he is once again running for the Senate.

He will take on Democratic Sen. Sherrod Brown, who has represented Ohio in the Senate for nearly 16 years. While Brown has yet to formally announce his 2024 run, he told Ohio's Spectrum News 1 in November that he will seek reelection.

"People recognize that I get up every day and fight for the dignity of work. Whether you swipe a badge or punch a clock or work for tips or work for a salary," he told Spectrum.

But with the exception of Brown, Republicans have maintained commanding control of statewide offices for over a decade. This gives Dolan confidence he can flip Brown's seat in 2024.

"Sherrod Brown isn't just out of touch with Ohio, after 30 [years] he's blind to the impact of his dangerous policies," Dolan tweeted Tuesday. "Talk with our law enforcement and sheriffs. Sit with our families impacted by overdose. We must secure the border to protect Ohioans and America's national security."

Indiana as a Republican microcosm of the party's future

Republicans have held the majority of government positions in Indiana for nearly 20 years, and that's not expected to change in 2024. In hopes of transitioning from the House to the Senate, Republican Rep. Jim Banks announced Tuesday that he aims to fill the shoes of Sen. Mike Braun, who is making a run for governor.

The former Navy Reserves officer said he's running for Senate to beat back President Biden and the Democrats to secure the nation's southern border, push for anti-abortion legislation on a federal level and fight to better support America's military and veterans.

He's running as a new-era Republican, one who won't make the same mistakes his predecessors did by cutting deals with Democrats.

"For too long, Republicans have gone along with Democrats' liberal spending priorities. I'm running for Senate to be part of the new generation of conservative fighters who say ENOUGH," he declared on Twitter Tuesday.

Former Indiana Gov. Mitch Daniels, also the former president of Purdue University, has been contemplating a Senate run as well. However, Daniels has been under attack by other right wingers, including Donald Trump Jr., who say he has betrayed the Republican Party.

"The establishment is trying to recruit weak RINO Mitch Daniels to run for US Senate in Indiana," Trump Jr. tweeted last week. "The same Mitch Daniels who agreed with Joe Biden that millions of MAGA Republicans are supposedly a danger to the country & trying to 'subvert democracy.' He would be Mitt Romney 2.0."

Indiana's 2024 Senate race will pit new Republican values against old, forcing voters to decide what the future of the party will look like moving forward.

Republicans launch a "Retire or Get Fired" campaign to remove Dems from GOP states

The NRSC said it's putting "red state Democrats" on blast for backing the president's agenda. Chairman Sen. Steve Daines, R-Mont., said in a statement Thursday: "These red state Democrats have a choice to make: retire or face a brutal two years in which they will be held accountable for backing Biden's disastrous agenda."

He accused Democratic Sens. Jon Tester of Montana, Joe Manchin of West Virginia and Sherrod Brown of Ohio of hurting their constituents with liberal policies, "and the NRSC is going to make sure voters back home know it."

All three senators are up for reelection in 2024 in states that Biden didn't win in the 2020 presidential election. In an attempt to push the politicians out of office, Senate Republicans are releasing ads across social media urging the three Democrats to not seek reelection. [Copyright 2023 NPR]