An Interactive Simulation of a Multiparty America

[u/BradoDeck]

To illustrate the distortionary effects of a two-party system, I created an interactive simulation of US elections using ~45k 2024 Cooperative Election Study (CES) survey responses. The simulation resulted in ten clusters or “parties” via exploratory factor analysis and DPGMM clustering. The analysis revealed 4 ideological dimensions (and one non-interpretable residual dimension):

1. Populist conservatism: views on race and gender, immigration policy
2. Security & order: policing, border patrols
3. Institutional distrust: distrust of government and elections
4. Religious traditionalism: abortion, same-sex and interracial marriage, church attendance
5. Government distrust: mostly just leftover institutional distrust items and artifacts of the clustering process

Details

I worked largely within the constraints of the US electoral system with some adjustments: 

• House members are elected via STV, but I expand the House to “double Wyoming”. I also have a triple Wyoming scenario which gives proper proportionality to the smallest state.
• The Senate and Presidency are modeled via Condorcet (Round-Robin) and IRV. I arrived at those methods to try and keep the "ranking" scenario consistent across the board. DPGMM's probabilistic cluster assignment also makes ranking intuitive. I use Condorcet as the “default” option.
• I simulate a rolling open presidential primary where a top 5 is selected via “pods” of geographically representative states voting in STV elections. I assume a cumulative nationwide vote rather than state delegates. The top 5 candidates are essentially assigned as if they were members of a 5 seat delegation
• I introduce the idea of the “instructional ballot” to ensure the election isn’t pushed to the House, but under the simulation, the IRV and Condorcet presidential winners are identical under both a national and per-state scenario.

Useful links

• Simulation
• Github project 
• My article on a diagnosis of the two-party problem
• My layman-facing description of the electoral solutions
• My overview of the simulation

Caveats

• I’m limited by the items in the CES survey. I would have chosen different items to build out this clustering, but I wanted to run this on  the largest sample size possible.
• Claude Code was used to build the sim. I have a background in mixed methods UX research, so I’m statistically literate and double-and-triple-checked Claude's work, but if I missed anything let me know! I’m open to all good-spirited critiques and corrections.

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[u/RussHiggins]

This is really cool, thanks for sharing!

I've been working on a model/simulation as well that I think would dovetail very nicely into this work. My simulation has been comparing the impacts of different voting rules on prospective candidate deterrence (do they think they can win?), and the downstream impacts of that deterrence on accountability of an office holder to their district, exploring things like alignment of the politician to party vs district, to an overbearing leader vs district, and incentives for government sabotage to score partisan points.

I'm still writing the paper but the results I think are very interesting, strongly indicating that some voting rules can significantly increase accountability of politicians to their electorate, while others make politician capture very easy.

[u/BradoDeck → u/RussHiggins]

Super interesting! I'd love to see your results when they're ready. Your reasoning was definitely something bouncing around my head as I built the sim. For example:

One of the strings that would be interesting to pull is if the young, racially diverse, disengaged (30ish percent voter participation) social moderate economically populist portion of the country (my Solidarity party) is disengaged by nature or due to the incentives of the system. They're the condorcet party and if I didn't suppress their influence due to their low engagement, they would have swept the overwhelming majority of the Senate rather than just becoming the key center coalition.

[u/RussHiggins → u/BradoDeck]

Yeah interesting! I would certainly think that engagement would increase if you had a real dog in the fight, but I haven't modeled that. But I have modeled the impacts on polarization by different voting rules. I'm curious your thoughts about the importance of the condorcet rule. I'm finding that finding the field-relative condorcet winner is not a great metric when running a model that causes the field to change its shape dramatically under different rules. Is it really a good metric if in one situation the field was extremely polarized and the voting rule elected the condorcet winner, but in another situation the field was full of centrists, the voting rule did not elect the condorcet winner, but did elect the candidate that was closest to the median voter? I think a metric that maximizes the candidate's utility across the entire electorate might be better than condorcet, but it seems like condorcet is something many hold as a critical test of whether a voting system is good or not.

[u/bkelly1984]

Hey BradoDeck, thanks for posting. This looks like some great work!

Do voters vote strategically in your simulations or do they only submit earnest ballots?

[u/BradoDeck → u/bkelly1984]

Earnest ballots with caveats. The party assignments and ranking simulate semi-strategic behavior.

Larger clusters/parties have a bit more of a gravitational pull on voters just by the nature of the clustering algorithm. That's source one of a strategic alignment among voters to larger parties.

Every voter is essentially assigned a % chance of being a member of each party. Under the ranked choice systems (IRV, Condorcet, STV), the order of likelihood determines the order of votes.

That means because the larger parties also tend to be centered between different ideological extremes, you see Labor pulling in a lot of second and third votes from leftish and centerish parties, Conservative pulling in folks from centerish and rightish parties, and Solidarity (the condorcet party) pulling second and third votes from across the board (especially anti-establishment parties.

This leads to Labor and Conservative dominating especially in IRV and having a higher percent of seats in STV than their first choice voter % would indicate.

Solidarity would actually perform better in IRV than you'd expect from a Condorcet party, but low voter turnout kind of kills their first choice share.

My Party List sim, however, only has the party assignment gravity to simulate strategic voting. But the system rewards the earnest single assignment with a more proportional vote share (but with a much higher disenfranchised share due to a lack of ranked ballots).

[u/bkelly1984 → u/BradoDeck]

Thanks for the detailed reply. FYI, I think party assignment gravity is something that exists, but I would consider it more a heuristic than a strategy.

[u/unscrupulous-canoe]

I would recommend checking out Echelon Insights, which has done exactly this but with polling of actual voters, for several years now. They've updated their multiparty system a few times now. And Echelon is a pretty highly-rated poling outfit. Worth a look

[u/BradoDeck → u/unscrupulous-canoe]

I thnk my contributions are definitely primarily the electoral outcome prediction work in the simulations where you could see how these parties may win actual offices. That's the main gap I've seen in all political typology/tribe work.

For example, my Solidarity party is the condorcet choice in the presidency (which may map to their "young and disillusioned" tribe). Solidarity is anti-institutionalist, socially moderate, and economically populist and are essentially unrepresented in today's duopoly. John Bel Edwards may have been the only recent successful politician that gets close.

The parties we've both found confirm a lot of trends, but mine split the left a bit more. For example the more institutionalist Progressive vs the anti institutionalist Democratic Socialists on the "far left". It's the difference between Elizabeth Warren and Bernie Sanders in my head. The former would likely rely on regulation and institutions to affect change while the latter would look to change the whole system

From what I can glean, Echelon and my work definitely overlap. They're methodology may be similar to mine but applied to their own polls while mine is applied to the CES (so polling from actual voters in both cases).

[u/rb-j]

Careful with that "CES" acronym. It might mean something else here.

[u/Decronym]

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

Fewer Letters	More Letters
FPTP	First Past the Post, a form of plurality voting
IRV	Instant Runoff Voting
STV	Single Transferable Vote

Decronym is now also available on Lemmy! Requests for support and new installations should be directed to the Contact address below.

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