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FORECAST51 DAYS OUT
← House3 November 2026 · 51 days out

LA-04 · U.S. House

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Mike Johnson is heavily favored to lead Louisiana’s first round. Predicted margin: R+28.8.

Mike Johnson (R)81 in 10081.4%64.0high 76.2 · low 51.9
Conrad Cable (D)19 in 10018.6%35.3high 47.4 · low 23.1
Other (minor parties / write-ins)—0.7high 1.7 · low 0.1

high / low: vote share (%) in the middle 80 in 100 simulations

Solid R80% range · first-choice margin R+36.9 to R+20.7Republican-held seat

Forecast history

Steady+0.1 pts · Sep 11 → Sep 13
Aug 1Nov 3 · Election Day

Latest reading · Sep 13 · first published Sep 9 · 80% range · margin points R+36.9 to R+20.7. Methodology

Hover the line, tap it, or use the arrow keys to inspect its history.

About this series

This comparable series begins on September 9, 2026, when the model version changed to CTMM 2.2. Earlier readings remain in the archive and are not joined as voter movement; faded points before September 9, 2026 are reconstructions, not forecasts issued on those days.

Faded: CTMM 2.2 reconstructed history: computed after the fact with each date's available polls and environment, without expert ratings; not an issued forecast. Issued forecasts begin at the launch marker.

How the margin was built

Follow each contribution to the margin. Wider ribbons mean more percentage points. Tap an input for its calculation and source.

Toward D+4.5
Toward R−33.3
Forecast marginR+28.8

The signed totals combine at the forecast. Displayed values are rounded.

All calculations & sources

This district's measured terrain −33.282 points

Call the Map's partisan lean on the CURRENT district lines, before any current-cycle evidence. Every pull below is measured from here — not from EVEN.

  • Call the Map partisan lean, district geography bound to this forecast edition.
  • Prior source: model_reconstructed_trial15_new_seat; district redrawn for 2026.

Fitted model, above the terrain shown +3.130 points

What the fitted model adds on top of the starting terrain above — incumbency, past results, campaign finance and the other fitted terms — measured from that terrain rather than from EVEN. It is a comparison with the starting point already shown, not a separate input. The source detail lists the variables the fit uses.

  • Fitted baseline -30.152 minus starting point -33.282 = 3.130 points.
  • Presidential-margin-by-congressional-district dynamic core.
  • Presidential-margin-by-congressional-district dynamic core (Jul 8 2026 deploy): a mass fit across district demographics, fundraising, incumbency, and past-cycle overperformance, trained on all 435 districts at once instead of a hand-built lean+incumbency recipe.
  • This district's lines changed for 2026 — the core weights its within-state redistricting position alongside the raw presidential margin.
  • The work: the core's fitted terms sum to −30.2 — the fundamentals row.
  • fundamentals core = 25-term dynamic formula (mass fit over the master feature matrix, held-out-cycle validated; see matrix/feature_dictionary.md + mass_fit_report.json)
  • 40-term formula, held-out validated.

National environment +1.365 points

The contribution to this race’s margin, not the national polling margin itself. The race’s loading, reference level and polling blend determine how much of the national climate reaches its final forecast.

  • Three-source blend, updated 2026-09-08: 52% generic-ballot aggregates (D+6.5) · 28% special-election overperformance (D+9.0 across 46 specials) · 20% approval-implied (D+8.6 from net approval -21.7).
  • Latest polls — generic ballot 2026-09-08 (5 days old), approval 2026-09-10 (3 days old).
  • Generic-ballot average D+6.5 · support factor 0.84 (the share of that channel's capacity the admitted polls carry) — separate inputs; their product is a capacity diagnostic, not a margin.
  • Weights are the 55/25/20 capacities scaled by each channel's evidence and renormalized, so thin polling widens the interval instead of pulling the center toward zero — 16% of the weight is carried that way.
  • Blended national environment: D+7.6.
  • Applied at full strength to this chamber's races.
  • The work: national environment × 1 chamber strength = +1.4 of this margin.
  • Blended national environment: D+7.6 (updated 2026-09-08).
  • Effective poll weight 84%; fundamentals share 16%, carried by the interval (×1.08) rather than by the center.
  • The support factor is the share of the generic-ballot capacity the admitted polls carry; average × support is a capacity diagnostic, not a margin, and is not what the row above multiplies.
  • Applied at full strength to this chamber: +1.4 of this margin.

The components this edition publishes for this race, in points. “Other factors” closes the sum to the two-party structural lean exactly. Here the structural lean IS the published margin, so the walk sums to the projection exactly; nothing is left over.

Named factorContribution
FundamentalsThe admitted fitted baseline. Its surviving variables differ by office; the source detail above identifies those used for this race.−30.15
National environmentThe national environment’s contribution to the prior. Polling can attenuate its influence; this value is not the national polling margin.+1.37
Other factors0.00

Recent elections

ElectionResultVotes cast
2024 · U.S. House ↗Not a D–R contestThe ballot was not a Democrat versus a Republican; a D/R margin cannot identify the winner.306,248
2022 · U.S. House ↗UnopposedOne named candidate in the retained source.1
2020 · U.S. House ↗Multiple-candidate ballotAt least one party total combines several candidates. It is not an individual candidate's result.306,578
2018 · U.S. House ↗R+31.3216,872

Historical district boundaries may differ. Margins compare Democratic and Republican vote totals. Nonstandard ballots are labeled separately.

The money

Bar length compares reported receipts in this race; the tick marks cash on hand. A missing filing stays blank rather than becoming $0.

One more fundraising reportCall the Map · $0

The candidates are comfortably out-fundraising the website covering them. A little rude, perhaps, but statistically unsurprising.

Received so far
$0
Measured compute
$26,188.58

Ko-fi and Buy Me a Coffee receipts are counted through Sep 1, 2026. Measured compute prices model runs at standard published API rates; it is not what I paid. Hosting, data and subscriptions, the domain and my own time are not counted. Donations buy gratitude, never a forecast adjustment.

Ko-fi ↗Buy Me a Coffee ↗

See the public support ledger →

No outside spending matched: Mike Johnson, Conrad Cable.

FEC filings · through 07/18/2026 · Definitions & method

Race context

Forecast votes cast
178,828
2024 presidential margin
R+34.6

Coverage

5 quotes

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