Democrats fresh off a triumph in the 2022 fight for the Senate now face an even more difficult battle: retaining their majority in the next election as they defend nearly two dozen seats.

Of the 33 Senate seats contested in 2024, 23 are held by Democrats, including a number in states that former President Trump won or nearly won. Republicans have their sights on taking down the likes of Sens. Joe Manchin (D-W.Va.), Jon Tester (D-Mont.) and Sherrod Brown (D-Ohio) and reversing the “candidate quality” issues that plagued them in 2022. 

Here are some issues to watch that could affect the battle for the Senate playing out over the next two years.

How will Schumer handle Sinema?

The moment Sen. Kyrsten Sinema (Ariz.) announced she was leaving the Democratic Party to become an independent, the 2024 cycle kicked off amid chatter on how each party will approach the seat. 

Senate Majority Leader Charles Schumer (D-N.Y.) is a key player in the Sinema dance. Will he treat her like a Democratic incumbent, as the party treats Sen. Angus King (I-Maine), or will he and the Democratic Senatorial Campaign Committee throw their weight behind a Democratic nominee?

Rep. Ruben Gallego (D-Ariz.) is already flirting with a challenge, but having a Democrat and Sinema in the race against a strong Republican candidate could easily flip the seat to the GOP.

Sinema’s decision to become an independent suggests she saw that as her best path to reelection, but she also faces uncertainty.

“It’s tough. It’s why you run as a Republican or run as a Democrat,” said Barrett Marson, a Phoenix-based GOP strategist. “But Sen. Sinema certainly has shown an ability to defy odds and win elections, close as they may be, in the state and has tapped into a lot of angst.”

Can the GOP fix its “candidate quality” problem?

Ever since Senate Minority Leader Mitch McConnell (R-Ky.) raised the issue of “candidate quality” in August, the item has loomed large for the party.

The GOP lost the Senate as candidates backed by Trump — notably Herschel Walker in Georgia, Blake Masters in Arizona and Mehmet Oz in Pennsylvania — were defeated.

Senate Republicans have signaled they are anxious for the National Republican Senatorial Committee to put its thumb on the scale in primaries again after a cycle where Sen. Rick Scott (R-Fla.), the committee’s previous chairman, refused to do so.

Sen. Steve Daines (R-Mont.), the newly-installed chairman, has signaled that change will happen.

“I will tell you this. If I have heard one thing since the last election a little over a month ago, Republicans are sick of losing, and we’re gonna do whatever it takes to win,” Daines told Fox News recently. “We want to make sure we have candidates that can win general elections.” 

Whether the party can cobble together a stable of winning candidates and what role Trump will play in the primary process are in question.

GOP strategists are also wondering if former Indiana Gov. Mitch Daniels (R) and Arizona Gov. Doug Ducey (R), who have turned down Senate bids in the past, will change their minds in 2024. Either would be a strong candidate in their states.

Can Democrats avoid a red state wipeout?

Republicans defeated a number of red-state Democrats in 2018, but Manchin and Tester survived.

Those two will be big targets in 2024 along with Brown in Ohio, which between 2018 and 2022 seemed to cement itself as a red state.

While Tester and Manchin have yet to reveal their 2024 plans, Brown has indicated he will seek a fourth term, giving a boost to Democrats.

Still, while Brown ran a strong race in 2018, he was aided by facing a weak candidate in then-Rep. Jim Renacci (R-Ohio), who entered the race at the last minute after former Ohio Treasurer Josh Mandel (R) dropped out. 

Whether he gets as lucky in 2024 remains to be seen. A number of Republicans, including Ohio Secretary of State Frank LaRose (R), may run for the right to face the incumbent Democrat.

In West Virginia, Rep. Alex Mooney (R) has announced a bid, while Gov. Jim Justice (R) and Attorney General Patrick Morrissey (R), who lost to Manchin in 2018, are considering the race.

Rep. Matt Rosendale (R-Mont.), who Tester defeated in 2018, and Rep.-elect Ryan Zinke (R-Mont.) are both reportedly eyeing the Montana race.

To retire, or not to retire? 

That is the question facing a number of Senate stalwarts who have yet to announce whether they will push for another term in the upper chamber. 

The list starts with Sen. Dianne Feinstein (D-Calif.), 89, the oldest member of the upper chamber who has been the subject of years of speculation over whether she will resign before her term is up.

Recently, Feinstein told the Los Angeles Times that she has no plans to step aside before the end of her term, but will decide in the spring whether to seek a sixth full term in office.

Democrats will be favored to win in California, and they’d also likely be favored in Maryland and Delaware, where Sens. Ben Cardin (D-Md.), 79, and Tom Carper (D-Del.), 75, have yet to announce reelection bids.

In other states, Democratic incumbents would have advantages, but not as great of a home field advantage.

Sen. Jacky Rosen (D-Nev.) told Politico she is “all in” on seeking a second term in 2024. Sens. Tammy Baldwin (D-Wis.) and Amy Klobuchar (D-Minn.) are also moving in that direction.

Nevada and Wisconsin, in particular, are states where Republicans will feel they have a fighting chance of picking up a seat. 

How will Trump affect the 2024 field? 

If there was a person the 2022 cycle revolved around, it was Trump.

Early signals show Trump may not have the kind of influence he held in this year in 2024.

The mere fact that Trump critic Sen. Mitt Romney (R-Utah) is considering a reelection bid and that Daniels is keeping the door open to one shows that Republicans aren’t running in fear of Trump. Noem gets a flamethrower for Christmas Republican Jewish Coalition says George Santos ‘not welcome’ at events after revelations

McConnell is also taking more public shots at Trump, signaling establishment GOP voices want to push back on his influence amid polls showing the former president behind Florida Gov. Ron DeSantis among GOP presidential voters.

Trump still has influence and allies within GOP circles, and predictions on his strength declining have been off in the past. 

What seems certain for now is that there will be a battle over his power and his ability to pick candidates, both in public and in private.