The Forecasting MachineOpen interactive report

Will Scott Colom (D) win the Mississippi U.S. Senate election on November 3, 2026?

Resolves Yes if Scott Colom (D) is certified as the winner of the Mississippi U.S. Senate seat contested on November 3, 2026, and No otherwise. If the contest is not decided on election night — because of a runoff, a ranked-choice tabulation, or a recount — it resolves on the final certified result. Declared candidates: Scott Colom (D); Cindy Hyde-Smith (R).

Forecasted on

Forecast probabilities

  • Yes: 11.2%
  • No: 88.8%

Reasoning

Scott Colom has an 11.2% chance of winning; Cindy Hyde-Smith is favored, with an 88.8% chance of victory. The late polling and Democratic investment make this more competitive than Mississippi’s history would suggest, but they have not erased the state’s strong Republican lean.

Yes: A Narrow Opening

The case for Colom begins with evidence that the race is not entirely routine. Cook shifted it from “Solid Republican” to “Lean Republican,” and an October Change Research poll put Hyde-Smith ahead by just 43% to 40% [e3] [e277, e278]. That result is a meaningful sign of a close contest, though it is one poll rather than several independent confirmations. An earlier poll also found a three-point gap, but it was sponsored by a progressive group and showed a generic Republican leading by 13 points [a3, a13] [e281].

Democrats have responded with substantial late support. The Senate Majority PAC committed $1.2 million, the DSCC added $500,000, and J.B. Pritzker’s PAC announced $1 million in advertising for Colom [e1] [e275] [e285]. Harris and Buttigieg campaigned with him, and a large Biloxi rally showed an ability to draw a crowd [e298] [e294, e297]. Colom also outraised Hyde-Smith in two quarters and led in reported ad spending, even though he entered the closing stretch with much less cash on hand [a1, a6] [a5, a14].

The broader environment offers some help: Democrats held a four-point generic ballot lead, while economic and policy concerns could give Colom a way to appeal beyond his party’s base [e308] [a5, a9]. If the close poll reflects more than sampling noise, and turnout or crossover support exceeds expectations, an upset is possible.

No: The State’s Partisan Gravity

The stronger case is the base rate. Trump carried Mississippi by nearly 23 points in 2024, Hyde-Smith defeated Mike Espy 54% to 44% in 2020, and Democrats have not won a Mississippi Senate race since 1982. No sitting Mississippi senator has lost reelection since 1942 [a2, a5, a10, a11]. Those are not guarantees, but they describe a durable advantage that a challenger must overcome.

The available polling has not shown Colom ahead. The latest survey still puts Hyde-Smith three points in front, and the earlier close poll came from a progressive sponsor; another poll circulated this year was later acknowledged to have fabricated most of its data, adding reason for caution about noisy evidence [e277, e278] [a3, a13] [e132, e134]. Hyde-Smith also has a cash advantage and support from Trump, who rallied with her in Mississippi [a5, a14] [e274, e280]. Republican outside spending is also part of the contest, with both parties’ aligned groups committing major sums [e276].

The national mood and Democratic mobilization may narrow the gap, but they do not by themselves establish that Mississippi voters have moved far enough to change the result. Colom still needs a substantial break from the state’s recent voting pattern.

How the Evidence Adds Up

The evidence points in two directions, but not with equal force. Close polling, a more favorable national climate, and unusually heavy Democratic spending justify giving Colom a real chance rather than treating the race as automatic. Yet the polls still show him trailing, and the state’s partisan history, Hyde-Smith’s financial position, and Trump’s support make a Republican win much more likely. That balance supports the forecast: Yes, 11.2%; No, 88.8%.

Update summary

Since the previous forecast, Pritzker’s PAC announced $1 million in advertising for Colom and the DSCC committed another $500,000 to a statewide campaign [e285] [e275]. Buttigieg’s Biloxi rally also drew about 1,000 attendees, adding a modest sign of campaign engagement [e294] [e297].

Cited evidence