May’s primary calendar could help determine control of Congress. A dozen states hold primaries and runoffs that put Trump-endorsed candidates and several competitive Senate and gubernatorial races in the spotlight. Key tests include Indiana’s redistricting backlash, Ohio’s high-profile governor and Senate matchups, Louisiana’s GOP Senate contest and pivotal showdowns in Georgia, Kentucky and Texas. Outside spending and narrow margins make this month especially consequential for the 2026 midterms.
May’s Primary Showdowns That Could Decide Control Of Congress
Ed Gallrein launched a congressional campaign to challenge Rep. Thomas Massie in Kentucky after President Donald Trump endorsed him. The announcement took place in the Oval Office at the White House in March.(Fox News)
The 2026 primary season returns in May with a packed calendar: a dozen states hold primaries or runoffs that could shape control of the House and Senate in November. Tight congressional margins, high-profile Senate contests and Trump-endorsed intra-party fights make this stretch a critical test for both parties.
Indiana Lt. Gov. Micah Beckwith announces the results of a vote to redistrict the state's congressional map at the Statehouse in Indianapolis on Dec. 11, 2025.
Key Dates
Primaries begin May 5 in Indiana and Ohio, with Nebraska and West Virginia on May 12. Louisiana votes May 16, and May 19 is the busiest day with contests in Alabama, Georgia, Idaho, Kentucky, Oregon and Pennsylvania. Texas concludes the month with runoff elections on May 26.
Sen. Bill Cassidy, R-La., seen speaking during a Senate Health, Education, Labor and Pensions Committee hearing in Washington, D.C., on Sept. 17, 2025, is facing a rough road to re-election this year.
Indiana: A Test Of Trump’s Influence
Indiana is one of the first major tests of former President Donald Trump’s sway over the GOP. Earlier this year, the Republican-controlled state senate rejected a congressional redistricting plan that would have added two right-leaning U.S. House seats. In response, Trump endorsed challengers to eight GOP state senators who opposed the plan. Outside groups, including Turning Point USA's political arm and the Club for Growth, have spent millions to back those challengers.
Rep. Thomas Massie arrives for a House vote on the funding bill to reopen the government in Washington, D.C., on Feb. 3, 2026.
Ohio: High-Profile But Relatively Quiet
Ohio’s primary calendar looks comparatively calm on the surface. Vivek Ramaswamy, the entrepreneur who gained national attention during the 2024 presidential cycle and who is backed by Trump, is heavily favored to win the GOP nomination for governor and will likely face Democrat Dr. Amy Acton in November. In the Senate race, appointed Republican Sen. Jon Husted is unopposed for the GOP nod, while former Sen. Sherrod Brown is expected to win the Democratic primary to serve the remainder of the seat vacated by Vice President J.D. Vance.
GOP candidates for Georgia governor, Rick Jackson, left, and Lt. Gov. Burt Jones, right, are pictured with President Donald Trump as they campaign as Trump loyalists.
Louisiana: A Three-Way GOP Fight
Sen. Bill Cassidy faces Republican challengers Rep. Julia Letlow and former Rep. John Fleming, now state treasurer. Trump has endorsed Letlow. Cassidy, who was among a small group of GOP senators who voted to convict Trump during the 2021 impeachment trial, has otherwise supported the president's agenda during Trump’s current term. Louisiana law requires a majority; if no candidate tops 50%, the top two advance to a June 27 runoff.
Incumbent Sen. John Cornyn, R-Texas, left, faces Texas Attorney General Ken Paxton in a GOP primary runoff election.
Kentucky 4th District: Massie vs. Gallrein
Rep. Thomas Massie, known for his libertarian-leaning stances and vocal criticisms of Trump on several issues, is defending his seat against Ed Gallrein, a former Navy SEAL backed by Trump. Pro-Trump groups have invested heavily in the race, making it another barometer of the former president’s endorsement power.
Georgia: Governor And Senate Battlegrounds
With Gov. Brian Kemp term-limited, the GOP gubernatorial primary features Lt. Gov. Burt Jones, who has Trump’s endorsement; major donor Rick Jackson, who has self-funded his campaign; Attorney General Chris Carr; and Secretary of State Brad Raffensperger. On the Democratic side, former Atlanta Mayor Keisha Lance Bottoms is a leading contender, joined by Mike Thurmond and former Republican lieutenant governor Geoff Duncan, who switched parties.
The Senate race in Georgia is also consequential. First-term Sen. Jon Ossoff is viewed as vulnerable, and the Republican primary has been contentious, featuring Reps. Mike Collins and Buddy Carter and Derek Dooley, who is backed by Kemp. Trump has remained neutral in the Georgia Senate primary so far.
Texas: Cornyn, Paxton And A High-Profile Runoff
Longtime Sen. John Cornyn narrowly advanced to a runoff against state Attorney General Ken Paxton after neither exceeded 50% in the March GOP primary. Trump has stayed neutral in the Cornyn-Paxton runoff. The GOP nominee will face Democratic state representative James Talarico, who raised roughly $27 million in the first three months of the year. Democrats warn a Paxton nomination could make the general election tougher for Republicans.
Why May Matters
Across these states, May’s contests combine tight margins in Congress, the potential electoral impact of Trump endorsements, heavy outside spending and a mix of statewide and local political dynamics. Several outcomes this month could materially affect which party controls the Senate and shape the battleground map heading into November.
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