The 2024 US Senate races are critical in determining which party will control the chamber in the next Congress, but before Republicans mount a challenge to the Democratic majority they must first navigate through what, in some cases, could be contentious primaries.

The Democrats have only one legitimate challenge opportunity within the field of 11 Republican defense states, Texas, but here as well, they feature a competitive battle for the party nomination. They are also likely headed to a rousing year-long double-Democratic jungle primary and general election in California and a hotly contested open intra-party battle in Maryland.

Arizona

In this wild card Senate race that will feature a three-way general election, two of the entries appear set. Sen. Kyrsten Sinema (I) has not yet officially announced that she will seek re-election, but all indications are that she will mount a vigorous campaign. The question remains as to whether she will run as an Independent or the nominee of a minor party, such as the No Labels Party that has qualified in her state. Rep. Ruben Gallego (D-Phoenix) appears as a lock to win the Democratic nomination.

On the Republican side, reports are surfacing the 2022 gubernatorial candidate Kari Lake is close to announcing her Senate effort. Pinal County Sheriff Mark Lamb is already a declared candidate. Early polling suggests that Ms. Lake would begin with a significant primary lead.

Though most Republican strategists blanch at another Lake run, it is important to remember that she received 49.6% of the vote in the Governor’s race. In the three-way Senate contest, 35-38% is likely all that’s necessary to win and she has strong base support. The Arizona primary is scheduled for August 6, 2024.

California

Sen. Dianne Feinstein (D) is retiring, and in her wake is a major political battle among three progressive left Democratic House members, Reps. Barbara Lee (D-Oakland), Katie Porter (D-Irvine), and Adam Schiff (D-Burbank). The big question coming from the jungle primary is whether a Republican, coalescing the minority party votes, can capture one of the two general election finalist positions because the Democratic vote will be so badly fractured.

Chances are Reps. Schiff and Porter, probably in that order, advance into what promises to be a contentious and very expensive open US Senate general election campaign. The California jungle primary is scheduled for Super Tuesday, March 5th.

Florida

Democrats have yet to find a credible opponent for Sen. Rick Scott (R), but he does have Republican opposition. Businessman Keith Gross, who reportedly has the wherewithal to fund his own campaign but has yet to make a substantial investment, is challenging Sen. Scott for renomination. Mr. Gross may be able to wage a battle against the Senator but toppling him for the nomination appears as a bridge too far. Sen. Scott appears in good shape for renomination and re-election. The Florida primary is late, August 20, 2024, so much time remains for a primary contest to take shape.

Indiana

Sen. Mike Braun (R) is leaving the Senate to run for Governor, and Congressman Jim Banks (R-Columbia City) appears to be the prohibitive favorite to succeed him in both the Republican primary and general election. At this point, no strong Republican has emerged, but that could change as we get closer to the February 9, 2024, candidate filing deadline. The Indiana primary is scheduled for May 7, 2024.

Maryland

Sen. Ben Cardin (D) is retiring, thus leaving what promises to be a very active Democratic succession primary. The two top contenders are Rep. David Trone (D-Potomac), who has enough personal money to spend millions of dollars on his race, and Prince Georges County Executive Angela Alsobrooks. The third contender, at this point, is Montgomery County Councilman and former congressional candidate Will Jawando. 

The key will be whether Ms. Alsobrooks can coalesce the state’s large black population and energize them to turnout for the primary election. She will be strong in PG County and Baltimore, which could control the party primary. Rep. Trone will run strong in the other areas of the state. This promises to be a hard fought contest with a potentially close outcome. The eventual Democratic nominee will have little trouble in the general election. The definitive Maryland primary will occur on May 14, 2024.

Michigan

Sen. Debbie Stabenow (D) is retiring after what will be four full terms in office, and likely leaves contested primaries in both parties. Democrats are favored to hold the seat, and the leading candidate in both the primary and general election is US Rep. Elissa Slotkin (D-Lansing).

In her primary, Michigan State Board of Education President Paula Pugh, actor Hill Harper, former state Rep. Leslie Love, and attorney Jaquise Purifoy comprise her key challenge group. All are African American, so the black vote will likely split, thus yielding a favorable campaign structure for Rep. Slotkin. As a prodigious fundraiser, she will also have a major financial advantage.

We have yet to see major candidate announcements on the Republican side, but a primary brewing between a pair of ex-Congressmen, Mike Rogers and Peter Meijer, could come to fruition. Either would give the Republicans a fighting chance to win the general election, but Michigan has swung leftward in the past two elections, thus making Rep. Slotkin the early favorite to succeed Sen. Stabenow. The Michigan primary is also late, August 6, 2024, so plenty of time remains for the campaigns to develop.

Montana

The Big Sky Country hosts one of the three key conversion opportunities the GOP must win to claim the Senate majority. Sen. Jon Tester (D) is on the ballot for a fourth term, but for the first time will likely be facing, what for him, will be an unfavorable political climate.

The Republican leadership is convinced that Rep. Matt Rosendale (R-Glendive) won’t win the general election and are backing retired Navy SEAL and aerospace company CEO Tim Sheehy. Mr. Rosendale has not yet launched a Senate campaign, but reports suggest he is close to doing so.

This primary contest has the potential of becoming very contentious and could damage overall GOP chances against Tester. If Rosendale enters the race, this will likely be the nomination campaign that draws the most attention in the early primary cycle. The Montana primary will be held June 4, 2024.

Nebraska

Sen. Ben Sasse (R) resigning earlier this year led to former Governor Pete Ricketts (R) being appointed to the seat. The new Senator must now run in a special election to fill the balance of the term, and then again in 2026 for a full six-year stint. Sen. Ricketts has already announced that he will run in both elections.

Republicans are safe here in the general election; thus, the primary could become the competitive race. So far, no major challenger has come forward, though rancher Chuck Herbster, who placed only second in the 2022 Governor’s primary despite having a Donald Trump endorsement, remains a potential candidate.

Sen. Deb Fischer (R), on the ballot for the regular term, has no opposition to date in either the primary or general elections. Nebraskans will choose their nominees on May 14, 2024.

Nevada

Sen. Jacky Rosen (D) is on the ballot for a second term, and the Republican primary is now becoming crowded. Sam Brown, the disabled Afghan War veteran is the National Republican Senatorial Committee’s choice and should be viewed as the leading candidate.

Earlier this week, former Ambassador to Iceland Jeff Gunter and Tony Grady, the retired Air Force officer and director of the Reno Air Aces, entered the race and could make the Republican primary interesting. The Nevada general election contest could well become a top tier challenge race. The Silver State primary is scheduled for June 11, 2024.

Ohio

One of the top three Republican conversion opportunities is the Ohio race featuring Sen. Sherrod Brown’s (D) run for a fourth term. Republicans have three major contenders: Secretary of State Frank LaRose, state Senator and 2022 US Senate candidate Matt Dolan, and businessman Bernie Moreno.

Early polling gives Mr. LaRose, who has won a statewide campaign, the advantage. Sen. Dolan, in his 2022 race, came on strong at the end and finished within one percentage point of second place. Mr. Moreno, who was also in the 2022 Senate race but withdrew before voting began, has earned Ohio junior Senator J.D. Vance’s (R) endorsement.

Regardless of who wins the Republican primary, the Buckeye State Senate campaign will remain a top tier challenge race. The Ohio primary will occur on March 19, 2024.

Pennsylvania

Little is occurring in the GOP nomination race as Sen. Bob Casey, Jr. (D) rallies his supporters in a quest for a fourth term. Republicans are confident that 2022 Senate candidate David McCormick (R) will enter the race, and the primary appears his for the taking. Mr. McCormick lost the 2022 Republican campaign to Dr. Mehmet Oz by just 950 votes statewide. Assuming he returns, Mr. McCormick will begin the general election contest as a decided underdog to Sen. Casey. The Pennsylvania primary will be conducted on April 23, 2024.

Texas

The Lone Star State Senate contest appears to be the Democrats only shot at developing a competitive challenge race. Sen. Ted Cruz (R) is on the ballot for a third term and must be considered a clear favorite in a state where Democrats still have not won a major statewide campaign in decades. In a presidential year, their task becomes even harder.

The Democratic leadership is backing US Rep. Colin Allred (D-Dallas), but he faces a serious challenge from state Senator Roland Gutierrez (D-San Antonio). The Senator is the top gun control advocate in the legislature and much closer to the party’s progressive left base than is Rep. Allred. Additionally, Texas state Senate seats are bigger than congressional districts, so Sen. Gutierrez actually represents 150,000 more people than does Rep. Allred. 

The Congressman has raised over $6 million since his announcement, but now must spend that and more just to win the party nomination. Sen. Cruz will use the primary to force both men further to the left on energy issues, which are so critical to the Texas economy. The Lone Star primary will be held on Super Tuesday, March 5, 2024.

Utah

The big question lingering in the Beehive State is whether Sen. Mitt Romney* (R) will run for a second term. The Senator says he will make a decision in the Autumn. If he does run, Mr. Romney faces a competitive Republican primary challenge, likely from state House Speaker Brad Wilson (R-Kaysville).

Sen. Romney has little chance of winning the state nominating convention, so to qualify for the ballot he will need to recruit 28,000 valid petition signatures from around the state. This process would allow him to bypass the party structure and go directly to the primary ballot. 

Republicans will hold the seat in the general election, but the political drama comes in the Republican primary where it is not inconceivable that Sen. Romney could lose. The nomination will be decided on June 25, 2024.

West Virginia

Sen. Joe Manchin (D) continues to waver about seeking re-election. He is again making statements that he could become an Independent or run for President as a minor party nominee. Regardless of his decision, the West Virginia race is the Republicans’ best conversion opportunity. Gov. Jim Justice (R) is an announced candidate in the Republican primary and faces US Rep. Alex Mooney (R-Charles Town).

The winner, likely Gov. Justice, will be considered the favorite for the general election in what has been Donald Trump’s second best state in the nation during both his 2016 and 2020 election campaigns. With the Club for Growth willing to spend millions to help Mooney from the outside, the Republican primary will be more competitive than one might believe at first glance. The victory odds, however, still favor Gov. Justice. The Republican nomination will be settled on May 14, 2024.

Wisconsin

The Badger State race is the Republicans’ biggest disappointment to date in terms of candidate recruitment. No one has yet come forward to challenge two-term Sen. Tammy Baldwin (D), and it’s possible that she could run without a serious challenge in what is typically a close state.

Should the congressional districts be redrawn, it is possible that Rep. Bryan Steil (R-Janesville) will find that entering the Senate race is his best political option. He would be the Republicans’ strongest contender. The Wisconsin primary is not until August 6, 2024, so time remains for Republicans to right their political ship.

*denotes candidate received an AGC PAC contribution during the 2023-2024 election cycle.