U.S. Senate

Why this race matters

This is the 28th closest Senate race in the forecast, 21.7 points, out of 35.

35 Senate races are on the 2026 ballot in this forecast (15 Democratic leads, 20 Republican leads). Seats that are not on the ballot are not assigned, so this is not a 100-seat chamber.

No earlier forecast of this race is archived, so there is no previous projection, date, or reason to show.

History block in the model: R+29.6. That is the office blend, not one past election.

Last same-office result in the candidate file: 2022 R+34.6. A special on the 2026 ballot is not automatically that contest.

Polling block: R+9.5. The published result is still the county sum.

Counties

Every reporting unit in the race. Tap a county to open its precincts. The projected votes above are this table added up. They are not ballots cast.

Counties

County	Leader	Party	Margin	Vote share	Projected ↓
Pulaski County	DHallie Shoffner, DHallie Shoffner	D	D+29.8	63.8%	120,617
Benton County	RTom Cotton, RTom Cotton	R	R+19.3	58.5%	100,769
Washington County	DHallie Shoffner, DHallie Shoffner	D	D+1.0	49.4%	76,134
Saline County	RTom Cotton, RTom Cotton	R	R+32.5	65.1%	45,143
Faulkner County	RTom Cotton, RTom Cotton	R	R+24.6	61.2%	42,680
Sebastian County	RTom Cotton, RTom Cotton	R	R+29.9	63.8%	35,617
Garland County	RTom Cotton, RTom Cotton	R	R+28.6	63.2%	33,168
Craighead County	RTom Cotton, RTom Cotton	R	R+29.8	63.7%	29,184
White County	RTom Cotton, RTom Cotton	R	R+53.5	75.6%	24,165
Lonoke County	RTom Cotton, RTom Cotton	R	R+46.0	71.9%	23,994
Pope County	RTom Cotton, RTom Cotton	R	R+44.5	71.1%	18,957
Crawford County	RTom Cotton, RTom Cotton	R	R+50.5	74.1%	18,676
Jefferson County	DHallie Shoffner, DHallie Shoffner	D	D+27.7	62.7%	16,932
Baxter County	RTom Cotton, RTom Cotton	R	R+49.2	73.5%	16,420
Boone County	RTom Cotton, RTom Cotton	R	R+57.3	77.5%	13,410
Greene County	RTom Cotton, RTom Cotton	R	R+53.5	75.6%	12,397
Miller County	RTom Cotton, RTom Cotton	R	R+43.4	70.6%	12,383
Union County	RTom Cotton, RTom Cotton	R	R+25.8	61.8%	12,105
Crittenden County	DHallie Shoffner, DHallie Shoffner	D	D+10.0	53.9%	11,504
Independence County	RTom Cotton, RTom Cotton	R	R+51.8	74.8%	10,979
Cleburne County	RTom Cotton, RTom Cotton	R	R+60.2	79.0%	9,982
Hot Spring County	RTom Cotton, RTom Cotton	R	R+44.5	71.1%	9,625
Carroll County	RTom Cotton, RTom Cotton	R	R+24.0	60.9%	9,041
Mississippi County	RTom Cotton, RTom Cotton	R	R+23.9	60.8%	8,398
Johnson County	RTom Cotton, RTom Cotton	R	R+43.8	70.7%	7,099
Ouachita County	RTom Cotton, RTom Cotton	R	R+11.4	54.6%	6,760
Conway County	RTom Cotton, RTom Cotton	R	R+32.6	65.2%	6,693
Polk County	RTom Cotton, RTom Cotton	R	R+62.8	80.3%	6,494
Logan County	RTom Cotton, RTom Cotton	R	R+54.5	76.1%	6,430
Grant County	RTom Cotton, RTom Cotton	R	R+61.2	79.5%	6,330
Columbia County	RTom Cotton, RTom Cotton	R	R+28.8	63.3%	6,222
Marion County	RTom Cotton, RTom Cotton	R	R+52.6	75.1%	6,152
Clark County	RTom Cotton, RTom Cotton	R	R+12.8	55.3%	6,001
Van Buren County	RTom Cotton, RTom Cotton	R	R+52.5	75.1%	5,972
Madison County	RTom Cotton, RTom Cotton	R	R+50.9	74.3%	5,878
Sharp County	RTom Cotton, RTom Cotton	R	R+55.0	76.4%	5,828
Poinsett County	RTom Cotton, RTom Cotton	R	R+55.8	76.8%	5,547
Ashley County	RTom Cotton, RTom Cotton	R	R+35.5	66.6%	3,994
Franklin County	RTom Cotton, RTom Cotton	R	R+49.9	73.8%	3,960
Randolph County	RTom Cotton, RTom Cotton	R	R+51.3	74.5%	3,770
St. Francis County	DHallie Shoffner, DHallie Shoffner	D	D+11.7	54.7%	3,749
Cross County	RTom Cotton, RTom Cotton	R	R+35.2	66.5%	3,712
Yell County	RTom Cotton, RTom Cotton	R	R+48.3	73.0%	3,680
Drew County	RTom Cotton, RTom Cotton	R	R+21.3	59.5%	3,616
Hempstead County	RTom Cotton, RTom Cotton	R	R+27.2	62.5%	3,460
Stone County	RTom Cotton, RTom Cotton	R	R+49.2	73.5%	3,425
Izard County	RTom Cotton, RTom Cotton	R	R+53.5	75.6%	3,366
Lawrence County	RTom Cotton, RTom Cotton	R	R+51.5	74.6%	3,233
Arkansas County	RTom Cotton, RTom Cotton	R	R+31.7	64.7%	3,151
Phillips County	DHallie Shoffner, DHallie Shoffner	D	D+24.2	61.0%	3,095
Fulton County	RTom Cotton, RTom Cotton	R	R+49.7	73.7%	2,865
Clay County	RTom Cotton, RTom Cotton	R	R+49.2	73.5%	2,822
Little River County	RTom Cotton, RTom Cotton	R	R+41.8	69.8%	2,783
Jackson County	RTom Cotton, RTom Cotton	R	R+36.3	67.0%	2,713
Sevier County	RTom Cotton, RTom Cotton	R	R+49.3	73.5%	2,678
Perry County	RTom Cotton, RTom Cotton	R	R+45.1	71.4%	2,605
Howard County	RTom Cotton, RTom Cotton	R	R+34.2	66.0%	2,541
Pike County	RTom Cotton, RTom Cotton	R	R+60.7	79.2%	2,476
Searcy County	RTom Cotton, RTom Cotton	R	R+59.8	78.8%	2,198
Desha County	DHallie Shoffner, DHallie Shoffner	D	D+6.1	51.9%	2,197
Chicot County	DHallie Shoffner, DHallie Shoffner	D	D+14.9	56.3%	2,188
Newton County	RTom Cotton, RTom Cotton	R	R+51.7	74.7%	2,142
Montgomery County	RTom Cotton, RTom Cotton	R	R+50.7	74.2%	2,106
Scott County	RTom Cotton, RTom Cotton	R	R+61.1	79.4%	1,923
Cleveland County	RTom Cotton, RTom Cotton	R	R+55.1	76.4%	1,917
Lincoln County	RTom Cotton, RTom Cotton	R	R+37.6	67.7%	1,916
Bradley County	RTom Cotton, RTom Cotton	R	R+26.5	62.2%	1,823
Prairie County	RTom Cotton, RTom Cotton	R	R+53.3	75.5%	1,818
Nevada County	RTom Cotton, RTom Cotton	R	R+27.3	62.5%	1,651
Lee County	DHallie Shoffner, DHallie Shoffner	D	D+14.4	56.1%	1,580
Monroe County	RTom Cotton, RTom Cotton	R	R+4.8	51.3%	1,525
Lafayette County	RTom Cotton, RTom Cotton	R	R+25.8	61.8%	1,321
Dallas County	RTom Cotton, RTom Cotton	R	R+17.0	57.3%	1,320
Woodruff County	RTom Cotton, RTom Cotton	R	R+20.1	58.9%	1,316
Calhoun County	RTom Cotton, RTom Cotton	R	R+49.4	73.6%	1,188

Model

1. Raw data

   2024 presidential baseline

   National R−D 1.5

   County presidential file. Not the 2026 result.

2. Raw data

   Generic ballot

   D 51.7 R 43.1 R−D -8.6

   National Wikipedia aggregate, 2026-10-30. State generic ballots, where a public poll exists, are mixed with the national swing for a race that does not have its own poll: ME, MI, NH, NY, OH. A state with no generic-ballot poll keeps the national swing and is not assigned a neighbor's.

3. Raw data

   Party identification

   Pew D+5 and Gallup D+10, blend R−D -7.3

   Pew NPORS 2026, identifiers plus leaners: Republican 43, Democratic 48. Gallup party identification plus leaners, first two quarters of 2026: Democratic 49, Republican 39. Pew is 55% of this blend and Gallup is 45%.

4. Model input

   National block

   R−D -8.1

   60% generic ballot and 40% party identification. The swing versus the 2024 presidential margin is what gets transmitted.

5. Model input

   Swing transmitted

   0.98 × -9.5 = -9.3

   This race has its own poll. The swing in the history blocks, before they shrink toward that poll, is the national block minus the 2024 presidential margin. Elasticity is shrunk halfway toward 1.

6. Model input

   History block

   R−D 29.6

   A year with no Democrat or no Republican is not scored as Republican minus zero. The missing party's votes are not the winner's partisan margin. Tom Cotton in 2020 is the case: the other name was a Libertarian, and Democratic votes landed on him. That year uses the presidential margin. An independent who was the real opponent is still scored as the opponent. Weights 2018 5 / 2024 35 / 2020 20 / 2022 40. If that office was on the ballot in 2022, that year takes the 40 and 2018 takes the 5. Otherwise 2018 keeps the 40. A missing year is filled with the 2020 result for the same office. Another office is not used. The year lines are Pulaski County, the largest county, not the state total: 2018 from 2020 presidential D+25.2 w5, 2024 from 2020 presidential D+25.2 w35, 2020 presidential (no Democrat or no Republican) D+25.2 w20, 2022 D+18.2 w40. The state number above is the vote-weighted sum. A 2024 county map is not copied forward unchanged.

7. Model input

   Electorate block

   R−D 18.4

   History reweighted by usual midterm turnout, plus half of the transmitted swing. Rural and presidential-only counties still move farther when the result is spread back to counties. That spread is ballot size, not the demographic file. Published ballots are the 2018 midterm canvass for this office, split by these modeled shares. They are not the 2024 presidential vote. The 2026 early-vote count is not inside this margin.

8. Model input

   Turnout block

   R−D 21.5

   Each county is weighted by its 2018 ballots divided by its 2024 presidential ballots. Small counties shrink halfway toward the state median. 2020 mail shares are not used.

9. Model input

   National environment

   R−D 16.4

   History plus the full transmitted swing. With no poll of this race, that swing is the state generic ballot mixed with the national block, or the national block alone.

10. Model input

    State environment

    R−D 19.7

    History plus 45 percent of the transmitted swing. This is a Senate and governor weight.

11. Model input

    State partisan lean

    R−D 30.7

    The 2024 presidential margin of this state, or of this district for a House race. It is heavier than the old state-environment block and is not shrunk toward the polling term.

12. Model input

    Trump popularity

    R−D -4.1

    New York Times approval average, October 29, 2026: 37.4% approve, 60.2% disapprove. Net approval -22.800000000000004. That is not a vote share. Four-tenths of the net is a margin, then scaled by this place's partisan lean (factor 0.45), so an unpopular president costs more in a Democratic state.

13. Model input

    Candidate favorability

    R−D 0.0

    Tom Cotton's 2020 race had no Democrat or no Republican. Republican minus zero is not favorability. That year uses the presidential margin in the history block instead.

14. Model input

    Demographics

    R−D 15.3

    One statewide block only. A county that is more college-educated or more nonwhite than the other counties in this race takes more of the transmitted swing, and a more rural county takes less. That changes this block, at its weight. It does not choose which counties move when the margin is spread back out. That spread uses ballot size. The shares are the 2012–2016 American Community Survey and the 2010 Census, from the 2018 county election-context file. Alaska is not in that file.

15. Model input

    Finance

    R−D 22.4

    No sourced spending edge. The block is history, or history shrunk toward the poll. It is not a finance model.

16. Model input

    Issues

    R−D 22.4

    No sourced issue score. Same treatment as finance. It is not a separate issue model.

17. Model input

    Polling

    R−D 9.1

    Individual polls 9.6 (80%) and the Wikipedia average 7.1 (20%). Named support R−D 8.5. Allocated support R−D 9.1. Named support does not move. Only the undecided line is split, 57.8% Republican and 42.2% Democratic. That is the 2024 two-party Republican share 65.7 moved halfway to 50 and capped at 60/40. A minor-party line is not published as its own candidate. Banned individual rows excluded: 0. No same-office polling miss was sourced, so none is added. Applied to the polling term: 0.00. Public pollsters: 2. Outliers: 2. Recency half-life 16 days. Sample weight n/(n+350). A registered-voter poll is 0.90. An internal poll, or a poll sponsored by one party, is weighted 0. It is not in the average. An internal-only file is dropped. A poll that names both parties is not an internal. A poll more than 8 points from the median of the others is cut in half. Pollster quality nudges that weight by only a few percent. The same rule is used on a House poll. House district polls are likely-voter polls only.

18. Model input

    Generic ballot weight

    R−D 19.7

    The generic ballot stays in the blend next to the independent polls. It is not shrunk toward the poll and an internal does not replace it. Weight 9.5%.

19. Model input

    Top line

    Not a House term

    Senate and governor are the top line. They are not moved by themselves.

20. Model input

    Candidate

    R+2.30 added whole

    Tom Cotton keeps the incumbent term of 2.3 after shrinkage. Overperformance is a separate term and is not added again here. Tom Cotton has held this office about 12 years, so 0.8 is added for long service. Under eight years is unchanged. Tom Cotton's 2020 race had no Democrat or no Republican. Beating a Libertarian, or a blank line, is not an overperformance against the other major party. These points are not watered down to the candidate weight. The candidate weight is a separate slice of the baseline. On a Senate or governor race with three public polls and no outlier, the points stop at that poll instead of moving past it.

21. Model input

    Scandal

    None

    No candidate on this ballot is scandal-defined.

22. Model input

    Endorsements

    R−D +0.30

    Trump endorsed Tom Cotton. The presidential lean here is R−D 30.7, so the endorsement helps 0.30. Ballotpedia, Endorsements by Donald Trump, 2026 tables, page updated August 5, 2026. A primary endorsement is counted when that person is the nominee. A lost primary, a candidate not on the ballot, and a withdrawn endorsement are not.

23. Model input

    Halfway floor

    Applied

    Presidential margin 30.7. A thin poll may not move the result more than halfway from the office baseline 29.6 to the polling term. Held at 19.4. One poll does not rewrite the race.

24. Model input

    Pooling

    35% of the way from each history block toward the polling term

    Otherwise the shrink is 35%.

25. Model input

    Prediction market

    95% win probability

    Tom Cotton 95.0% is a win probability, not a vote share. Republican win probability 95.0 from Kalshi 94.6% Republican; Polymarket 95.5% Republican. A price of 50 is a tie. Each point above 50 is 0.35 margin points, capped at 12, so the raw margin is 12.0. That margin is shrunk 40% toward the pre-market margin 22.0, which leaves 16.0. It enters once, at 2.5%. The polling term is not nudged. The market and the polls differ by more than 15 points of win probability, so the weight is half of 5% and the interval is wider.

26. Model input

    State bend

    None

    Not applied.

27. Model input

    State environment adjustment

    R−D -0.6

    The 2022 statewide margin was R−D 27.8 and the 2024 presidential margin was R−D 30.7. The country moved 1.4 from that presidential vote to the 2022 House vote. Fifteen percent of the difference is kept, capped at 1.5, so the state environment is -0.6 on top of the national swing.

28. Model input

    Early vote

    D+0.6

    Party is on the file, but there is no 2022 same-day comparison, so the raw lead is not the adjustment. Ballots that match a 2024 presidential county sit at R−D 26.9. The 2024 vote in the same counties was R−D 30.6. The early mix is D+3.8 relative to that vote. Fifteen percent is kept, capped at 1, so D+0.6. This is where the ballots were cast. A more college-educated or more nonwhite county still takes more of the national swing in the demographics block, and a more rural county takes less. That block is separate from this point. This is not a count of how anyone voted, and not another model's estimate of the electorate.

29. Model input

    Other ratings

    R−D 11.5 at 3.0%

    Cook, Sabato, Inside Elections, and the other columns on the same published tables (Decision Desk HQ, RealClearPolitics, Split Ticket, FiftyPlusOne, The Economist, Fox News, Silver Bulletin). 10 ratings, average R−D 11.5. A toss-up is 0, tilt 1.5, lean 3.5, likely 7, safe or solid 12. If this race is already further to that side, the rating does not pull it back. Mixed in after everything else, at 3.0 percent. It does not replace the poll. A seat nobody has rated is left alone.

30. Model input

    Weights

    polling 21.3% · generic 9.0% · stateLean 14.5% · trump 9.6% · favorability 8.9% · history 6.4% · candidate 4.8% · national 4.8% · electorate 4.0% · stateEnv 3.2% · turnout 2.4% · demographics 2.4% · finance 1.6% · issues 1.7% · market 2.4% · ratings 3.0%

    History is lighter. State partisan lean, Trump popularity, and candidate favorability are their own terms. A market, when it qualifies, scales every other weight and is not taken out of polling alone. Published ratings, when a race has them, are mixed in after that. They are not taken out of polling alone.

31. County-sum margin

    21.7

    This is the sum of the county projections. Counties are not moved afterward to force this total.

32. Minor parties

    None

    Other is the 2024 presidential vote that was neither Democratic nor Republican, weighted by these counties. It is not the last forecast. A missing opponent is not Other. No Libertarian, Green, Constitution, or other minor line was on this ballot.

33. 80% interval

    11.1 to 32.4

    10th to 90th percentile of 50,000 draws. Poll, national, state, turnout, and candidate error.

34. 95% interval

    5.5 to 38.1

    2.5th to 97.5th percentile. Senate and governor state errors in the same state share a correlation of 0.30. The band shown is the marginal interval.