Background
Susan Collins is a Republican U.S. Senator from Maine who has served since 1997. She has historically outperformed typical Republican candidates in Maine, positioning herself as a moderate in a state that leans Democratic overall.
A January 2025 political science paper titled "The Electoral Consequences of Ideological Persuasion: Evidence from a Within-Precinct Analysis of U.S. Elections" by Bonica, Rhee, and Studen examines how candidate ideology affects vote share. The paper finds that a standard deviation change in ideological midpoint between candidates results in an average vote share penalty of 0.6 percentage points, with the authors concluding that "gains associated with ideological moderation are relatively modest and likely secondary to turnout effects."
Matthew Yglesias has challenged this paper's conclusions, suggesting that moderates like Susan Collins consistently outperform their state's partisan baseline, contrary to the paper's findings that ideological moderation offers only modest electoral advantages.
Resolution Criteria
This market will resolve to YES if Susan Collins outperforms the Republican partisan baseline in Maine by any margin in the 2026 Senate election, supporting Yglesias's position that moderate candidates like Collins do gain significant electoral advantages from their ideological positioning.
The market will resolve to NO if Susan Collins underperforms relative to the Republican partisan baseline in Maine in the 2026 Senate election.
The market will resolve to N/A if Susan Collins does not run for re-election in 2026.
The partisan baseline will be calculated by averaging Republican performance across other major statewide races in Maine during the 2024 and 2026 election cycles (including presidential, gubernatorial, and other federal races as applicable)
Clarification: Methodology for "Republican Baseline"
To ensure the "Republican Partisan Baseline" is robust and not reliant on a single data point (the Governor's race), the baseline for 2026 will be calculated by averaging the Republican vote share across three distinct statewide aggregates.
The 2026 Republican Baseline will be the arithmetic mean of:
The Gubernatorial Vote: The percentage of the vote received by the Republican candidate for Governor of Maine.
The Aggregated U.S. House Vote: The total number of votes cast for Republican candidates in ME-01 and ME-02 combined, divided by the total votes cast in both races.
The Aggregated State Legislative Vote: The total popular vote cast for all Republican candidates for the Maine State Senate and Maine House of Representatives, divided by the total votes cast only in those districts where a Republican candidate appears on the ballot.
Resolution Calculation:
If Susan Collins' vote share in the 2026 U.S. Senate election exceeds this calculated percentage, the market resolves YES.
1,000Hey! Great market! Are you pretty well set on the Baseline calculation? ALL lower offices, State and local, experience a natural occurring "drop off": Voters tend to stop at some place bc they aren't familiar with down card items- even like state reps (like a pop quiz they didn't study for) - With this in mind, Collins could beat the baseline and still lose??! right? Seems strange. Would you consider setting the baseline based on the total "Trump vote" statewide in 2024? Thanks!!
if I'm understanding correctly, wouldn't this market likely resolve no in the event susan collins does slightly better than other statewide republicans in 2026, but the environment is significantly bluer than 2024? I'm not sure how likely that scenario is, but I think the methodology here is questionable for answering the question at hand
@FreshFrier hmm, let me think about this. There’s only like… one other statewide race that year, so this is just “Will she outperform the governor candidate”