Hardest Republican Holds (In Order of Increasing Trump Vote Share)

MAINE, Sen. Susan Collins (ME-R): In 2020, Susan Collins survived a challenge even as Biden carried the state. It is unclear if voters will continue to split their ballots or if Democrats will be better-positioned during the 2026 mid-term election. Maine is the only state with a Republican Senator where Kamala Harris was victorious.

• 2024 Presidential Election:Trump 45.5%/ Harris 52.4%.

• Gov. Janet Mills (D) lost the primary to oyster farmer and veteran Graham Platner. (Gov. Janet Mills of Maine to Run for US Senate. NYT, 2025 October 14)

• Graham Platner wins Maine Democratic primary, setting up key race against Sen. Susan Collins. (WBUR, 2026 June 10)

NORTH CAROLINA, Open Seat (vacated by Sen. Thom Tillis (NC-R)): In 2020 Tills narrowly avoided losing when opponent Cal Cunningham’s extra-marital affair became public.

• 2024 Presidential Election: Trump 50.9% / Harris 47.6%.

• Backed by President Trump, Republican nominee is former chair of the National Republican Committee, Michael Whatley.

• The Democratic nominee is popular two-term governor Roy Cooper (D-NC).

ALASKA, Dan Sullivan (AK-R): An anti-abortion Senator in a heavily pro-choice state, Sullivan faces his first post-Dobbs election in a state that can break its partisan mold. In 2022 midterms, Alaskans elected Mary Peltola (D) along with the most anti-Trump Republican Senator currently serving, Lisa Murkowski (R). In 2024, in response to the veto of education funding by its Republican governor, Alaskans elected coalition legislative majorities in both chambers composed of Democrats, Independents, and moderate Republicans. 

• 2024 Presidential Election: Trump 54.4% / Harris 41.4%; Primary August 18, 2026.

• Former At-Large Alaska US Representative, Mary Peltola, is the Democratic Senate nominee. She won two elections in 2022 and lost in 2024 to Nick Begich, 48.8%.to 51.2%.

• Sabato’s Crystal Ball Moves Alaska Senate Race to Toss-Up, Boosting Mary Peltola Campaign. (Native News Online, 2026 June 11.)

• The At-large Alaska US House seat is also a top Democratic target in 2026. 

OHIO, Open Seat (vacated by Republican): The Senate seat is currently held by Jon Husted (R) who was appointed to fill Sen. JD Vance’s seat.

• 2024 Presidential Election: Trump 55.1% / Harris 43.9%.

• In August, former Senator Sherrod Brown launched his campaign to regain his seat, which he lost in 2024 to Bernie Moreno, 46.5% to 50.1%.

• Poll finds Sherrod Brown 8 points ahead of Jon Husted in Ohio’s U.S. Senate race. (NBC4, 2026 June 06)

IOWA, Open Seat (vacated by Republican Joni Ernst): In recent cycles Democrats have wavered between 43%-45% of the vote. In late August of 2025, Ernst declared that she will not seek re-election.   

• 2024 Presidential Election: Trump 55.7% / Harris 42.5%.

• Competitive US House races in Districts 1 and 3, which cover half of Iowa, are potential Republican defeats and likely to also attract organizing and resources. 

• The Republican candidate is Rep. Ashley Hinson (IA-R), a MAGA and Trump loyalist who is currently representing Iowa’s 2nd Congressional District.

• The Democratic nominee is Josh Turek, a state representative from Trump-leaning Pottawattamie County in western Iowa. His win has ignited Democrats nationwide, learn more about him through his campaign video, “Underdog.”

• Karl Rove Warns Strong Democrats Could Flip Iowa Senate Seat. (Just The News Iowa, 2026 June 08).

FLORIDA, Open Seat (vacated by Republican): Former Atty. Gen. Ashley Moody has been appointed to Sen. Marco Rubio’s vacated seat.

• 2024 Presidential Election: Trump 56.1% / Harris 43.0%; Primary August 18, 2026.

• The 2025 April 1st special elections for two House seats vacated by Matt Gaetz and Michael Waltz showed nearly 20 point swings to Democratic voters, possibly keying up a competitive 2026 Senate race in Florida.

• In January 2026, Alex Vindman (Trump impeachment whistleblower) declared his candidacy.

• Alex Vindman campaign polling shows him within striking distance of Ashley Moody. (Florida Politics, 2026 May 28)

TEXAS, Sen. Jon Cornyn (TX-R): Sen. Cornyn lost to MAGA primary challenger in Atty. Gen. Ken Paxton (R). A nasty primary, combined with Trump backlash and the right opposition candidate, could spell trouble for Republican control of this seat. 

• 2024 Presidential Election: Trump 56.1% / Harris 42.5%.

• Democratic nominee is Representative James Talerico.

• NEW POLL: JAMES TALARICO LEADS KEN PAXTON IN TEXAS SENATE GENERAL ELECTION. (Texas Public Opinion Research on Substack, 2026 May 20)

MONTANA, Open Seat (Vacated by Republican): Senator Steve Daines announced his retirement literally minutes before the March 4 filing deadline, which paved the way for his chosen successor, Republican U.S. Attorney Kurt Alme. The Democratic candidate is Alani Bankhead, but Independent Seth Bodnar has the tacit endorsement of former US Senators Jon Tester and Max Baucus among many others.

• 2024 Presidential Election: Trump 58.4% / Harris 38.4%

• A Montana senator declines re-election run, opening door for an independent candidate. (NPR, 2026 March 27)

• A G.O.P. Senate Seat in Montana Seemed Vulnerable. Then, the Left Splintered. (NYT, 2026 June 15)

• Election Guide 2026: Seth Bodnar (Montana Free Press, updated on 2026 June 15)

• Election Guide 2026: Alani Bankhead (Montana Free Press, updated on 2026 June 15)

NEBRASKA, Sen. Pete Ricketts (NE-R): Sen. Ricketts faces Independent Candidate Dan Osborn, who challenged Deb Fischer in the 2024 Senate election. He lost with 46.5% of the vote the Deb Fisher’s 53.2%.

• 2024 Presidential Election: Trump 59.3% / Harris 38.9%.

• In 2024 Dan Osborn over-performed better-funded candidates leading to renewed interest in Independent candidates challenging Republicans in red states. In 2026 Osborn hopes to secure earlier funding and unseat Ricketts in a battle framed as being between “the union mechanic” and “the son of billionaires.”

• Dan Osborn submits signatures to challenge Ricketts on Nebraska’s November ballot. “Unlike in his 2024 bid against U.S. Sen. Deb Fischer, R-Neb., Osborn is a known commodity and in the crosshairs of national and state Republicans. Also, Nebraska Democrats are clearing the field for Osborn this time around.” (Nebraska Examiner, 2026 June 11)