New Hampshire · Senate
election 2026-11-03 · forecast as of 2026-10-01 · margins and probabilities are for Chris Pappas
Who is running?
Chris Pappas (Democratic), John E. Sununu (Republican), Edmond J. LaPlante Jr. (Constitution). The margin below is Chris Pappas minus the other candidate in the main contest; the rest are on the ballot and not in it.
The race, in brief
New Hampshire's Senate seat is open: Democratic incumbent Jeanne Shaheen, first elected in 2008 and re-elected in 2014 and 2020, is not seeking a fourth term, making this the first open Senate election in the state since 2010. The text describes the state as slightly to moderately blue at the federal level, with Kamala Harris carrying it by roughly 3 points in 2024, an all-Democratic congressional delegation since 2017, and Republican control of the governorship and both legislative chambers. The state profile records a white non-Hispanic share of 0.9 and a college share of 0.4.
The Democratic nominee is U.S. representative Chris Pappas, who won the September 8 primary with 65% against medical scientist Karishma Manzur. The Republican nominee is former senator John E. Sununu, who held the seat from 2003 to 2009 until Shaheen defeated him; he won his primary with 68.4% (75,839 votes) over former Massachusetts senator Scott Brown's 26.6%. Constitution Party candidate Edmond LaPlante is also declared. As of August 19, 2026 Pappas had raised $15,384,657 with $4,251,918 on hand, Sununu $4,124,582 with $3,019,794 on hand.
The Cook Political Report (September 23, 2026) and Inside Elections (September 17, 2026) rate the race Tossup; CBS News, Decision Desk HQ, The Economist, FiftyPlusOne, Fox News, RealClearPolitics, Sabato's Crystal Ball, Silver Bulletin and Split Ticket list it as D. The polling average in the text is Pappas 47.7%, Sununu 41.8%. The latest listed poll, Trafalgar Group (R), September 26–27, 2026, has Pappas 47%, Sununu 41%; New York Times/Siena (September 15–22) has Pappas 50%, Sununu 45%.
A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.
The facts, each beside its sentence
Democratic incumbent Jeanne Shaheen is not seeking a fourth term.
This will be the first open Senate election in New Hampshire since 2010.
Democratic congressman Chris Pappas and Republican former senator John Sununu are the nominees for their respective parties.
Democratic congressman Chris Pappas and Republican former senator John Sununu are the nominees for their respective parties.
Chris Pappas, U.S. representative for 1 (2019–present)
Sununu, who held the seat for one term until he was defeated by Shaheen in 2008, won the Republican nomination
with Kamala Harris carrying the state by roughly 3 percentage points in the 2024 presidential election
Shaheen was first elected in 2008, defeating incumbent John Sununu in a rematch of 2002, and was reelected in 2014 and 2020.
Pappas won the Democratic nomination with 65% of the vote against medical scientist Karishma Manzur.
The Cook Political Report Tossup September 23, 2026
Campaign finance reports as of August 19, 2026 Candidate Raised Spent Cash on hand |Chris Pappas (D) $15,384,657
Average |47.7% 41.8% 10.5% |Pappas +5.9%
New York Times/Siena University September 15–22, 2026 613 (LV)
The state's congressional delegation has been entirely Democratic since 2017. However, Republicans control the governorship, both state legislative chambers, and a majority in the executive council.
Jeanne Shaheen, incumbent U.S. Senator (2009–present) (endorsed Pappas)
Edmond LaPlante (Constitution), member of the Monadnock Regional School Board and chairman of the Constitution Party of New Hampshire
Not in the source: The facts carry no forecast basis, so it is not stated what polls or priors the model rests on.; The text gives the Pappas primary share as 65% in the lead but the Democratic primary results table is garbled and gives no vote counts; the lead also says Sununu won 68.5% while the results table says 68.4%.; No 2020 presidential result or prior Senate margins are given as numbers.; Endorsement sections are empty in the text.
Read from the district's section of Wikipedia's state page (CC BY-SA), archived as 8d2527483f8e; written by claude-fable-5-1 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.
Who holds the seat now
Jeanne Shaheen (Democrat), in this chamber since 2009, 3 terms, class 2 (term ends 2027). Committees: Senate Committee on Appropriations; Senate Committee on Armed Services; Senate Committee on Foreign Relations (Ranking Member); Senate Committee on Small Business and Entrepreneurship; Senate Select Committee on Ethics; Commission on Security and Cooperation in Europe.
Margaret Wood Hassan (Democrat), in this chamber since 2017, 2 terms, class 3 (term ends 2029). Committees: Senate Committee on Finance; Senate Committee on Health, Education, Labor, and Pensions; Senate Committee on Homeland Security and Governmental Affairs; Senate Committee on Veterans' Affairs; Joint Economic Committee (Ranking Member).
From the congress-legislators dataset (CC0), archived as ae8cb9477c48. For a Senate race this lists both of the state's senators; the one whose term ends in the election year holds the seat on the ballot. For a House district redrawn for 2026 it is the member elected under the old lines with this number, who may be running elsewhere; the dossier above names who is running here.
The money
| Candidate | Raised | Cash on hand | PAC share | Self-funded | Outside $ for | Outside $ against |
|---|---|---|---|---|---|---|
| Pappas, Chris (DEM) open seat | $15,384,657 | $4,251,918 | 7% | 0% | $1,187 | $1,242,083 |
| Sununu, John E (REP) open seat | $4,180,252 | $3,070,033 | 10% | 0% | $2,887,182 | $130,636 |
| Brown, Scott P. (REP) open seat · not on our roster | $2,150,452 | $416,542 | 6% | 0% | $0 | $0 |
| Manzur, Karishma (DEM) open seat · not on our roster | $415,081 | $103,945 | 0% | 6% | $2,832 | $0 |
| Shaheen, Jeanne (DEM) incumbent · not on our roster | $172,667 | $871,923 | 32% | 0% | $0 | $0 |
| Sullivan, Jared (DEM) · not on our roster | $100,112 | $0 | 0% | 13% | $0 | $0 |
| Innis, Dan (REP) open seat · not on our roster | $48,503 | $0 | 0% | 0% | $0 | $0 |
| Giovonizzi, Matthew S (NON) open seat · not on our roster | $4,463 | $1,236 | 0% | 41% | $0 | $0 |
FEC bulk candidate summaries through August 19, 2026; $4,263,920 of independent expenditures for or against these candidates this cycle (FEC Schedule E, types 24E and 24A), which is the parties' and outside groups' own revealed view of whether this seat is in play.
How it has voted for president
| Two-party margin | 2016 | 2020 | 2024 |
|---|---|---|---|
| President | D+0.4 | D+7.5 | D+2.8 |
A shift of 2.4 points toward the Democrats from 2016 to 2024. county returns summed; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.
The state in numbers
| Measure | State | Average state | Difference |
|---|---|---|---|
| Bachelor's degree or higher, 25+, 2023 | 39.8% | 34.0% | +5.8 pts |
| White, non-Hispanic, 2023 | 87.5% | 66.3% | +21.3 pts |
| Black, non-Hispanic, 2023 | 1.4% | 10.1% | -8.7 pts |
| Hispanic or Latino, 2023 | 4.5% | 12.9% | -8.3 pts |
| Asian, non-Hispanic, 2023 | 2.6% | 4.4% | -1.8 pts |
| Foreign-born, 2023 | 6.2% | 9.6% | -3.4 pts |
| Median age, 2023 | 43.2 | 39.1 | +4.12 |
| Median household income, 2023 | $95,628 | $77,633 | $+17,995 |
| Median home value, 2023 | $367,200 | $314,132 | $+53,068 |
| Owner-occupied homes, 2023 | 72.5% | 67.4% | +5.2 pts |
| Unemployment (ACS), 2023 | 3.4% | 4.8% | -1.4 pts |
| Federal government workers, 2023 | 2.5% | 3.0% | -0.6 pts |
| Work from home, 2023 | 15.1% | 12.3% | +2.8 pts |
| Households on SNAP, 2023 | 6.0% | 11.1% | -5.1 pts |
| Households with Social Security income, 2023 | 34.3% | 32.1% | +2.2 pts |
| Households with public assistance income, 2023 | 2.4% | 2.6% | -0.2 pts |
| Moved in from another state, past year, 2023 | 3.7% | 2.9% | +0.8 pts |
| Gini index, 2023 | 0.44 | 0.47 | -0.02 |
| Unemployment, latest month (BLS), 2026-07 | 2.7% | 4.0% | -1.3 pts |
| Change in unemployment, past 12 months, 2026-07 | -0.5 pts | -0.1 pts | -0.3 pts |
| Change since the last election (24 months), 2026-07 | -0.1 pts | -0.1 pts | -0.0 pts |
| Per-capita personal income (BEA), 2024 | $83,192 | $70,662 | $+12,530 |
| Per-capita income growth since 2019, nominal, 2024 | 30.1% | 32.4% | -2.3 pts |
| Government and other transfers, share of income, 2024 | 16.1% | 19.4% | -3.3 pts |
| Social Security, share of income, 2022 | 6.2% | 6.1% | +0.1 pts |
| Medicare, share of income, 2022 | 3.7% | 4.4% | -0.6 pts |
| Medicaid, share of income, 2022 | 2.4% | 3.8% | -1.4 pts |
| SNAP, share of income, 2022 | 0.2% | 0.6% | -0.4 pts |
| Earned Income Tax Credit, share of income, 2022 | 0.1% | 0.3% | -0.2 pts |
| Veterans' benefits, share of income, 2022 | 0.7% | 0.9% | -0.2 pts |
| Federal civilian jobs, share of all jobs, 2022 | 0.9% | 1.5% | -0.6 pts |
| Military jobs, share of all jobs, 2022 | 0.4% | 1.2% | -0.7 pts |
ACS 5-year state tables; BLS county unemployment and BEA county income, transfers and jobs summed to the state. Every figure is a named column of a named public-domain table, archived before it was read.
Who is ahead, and by how much?
Two numbers because they answer two questions. The nowcast is where opinion stands; the election-day forecast is where it is likely to end up.
How likely is each to win?
Monte Carlo error is ±0.2 points. A change smaller than that is simulation noise rather than news, and this page will not describe it as movement.
How wide is the range?
Nowcast: 90% of simulations fall between -5.8 and +11.9 points. Election day: -5.7 to +16.1. The election-day interval is 4.1 points wider, which is the 33 days of movement still to come.
What is the uncertainty made of?
Total sd 6.96 points, made of race-specific polling error 51%, drift to election day 33%, correlated polling error 12%, latent opinion 3%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.
What evidence is this built on?
25 polls, most recent 2026-09-27. 23% verified against a primary source.
What changed since the last run?
Shaded band is the 90% interval, line is the central estimate, positive is Chris Pappas ahead of Edmond J. LaPlante Jr.. Over 18 stored forecasts the central estimate moved +0.8 points. There were 7 specification changes (marked on the axis) and 2 new polls arrived over this window — so the movement mixes new evidence with changes to the model.
Since 2026-10-01: margin +0.00 points, win probability +0.0 points, on +0 polls.
Not answered here: why it changed. Splitting a move into new polls, time and specification means re-running the earlier model against the later inputs -- two extra posterior fits -- so it is computed on a cadence (scripts/attribute_forecasts.py) rather than while you wait. This pair of runs has not been decomposed yet. The size of the move is shown; the cause is not guessed at.
How has this model done before?
Measured on 230 forecasts across 230 races in cycles 2016,2018,2020,2022,2024: mean absolute error 4.56 points, Brier score 0.0543. The nominal 90% interval contained the result 94% of the time, the 80% interval 84%, and the 50% interval 47%. Read that with care: a national polling miss moves every race in a cycle at once, so the sample size for a question about the intervals is 5 cycle(s), not 230 forecasts. Per cycle -- bias +1.644 pts; 2016: n=43 bias=+4.68 cov90=0.860; 2018: n=63 bias=-0.52 cov90=1.000; 2020: n=35 bias=+5.44 cov90=0.886; 2022: n=54 bias=-0.60 cov90=0.944; 2024: n=35 bias=+1.48 cov90=1.000.
Where did every number come from?
Nowcast run 2fee7bbd-08f3-42a8-b920-d11ab63ba724 and election-day run 6effed82-5419-487b-b6f3-54643f10c318, model single_race_latent/0.8.1 at commit bdf7e83107c17a2399efe61a44ef1bbee48f9284, seeds 20260924 and 20260924.