The Duverger Syndrome is democracies' most critical illness. Both the causes and the fixes are known. Solutions must be applied as a matter of priority.
In most single-choice voting systems, parties cannot field multiple candidates in a general election without splitting their vote and handing victory to the other side. The solution — and it is a solution to a problem the voting method itself created — is to hold a primary election first: an internal contest that narrows the field to a single candidate before the real race begins.
The primary electorate is not the same as the general election electorate. Primary elections are typically low-turnout affairs, attracting the most motivated, most ideologically committed, most partisan members of each party. The median primary voter sits considerably further from the political centre than the median general election voter. In some districts, the gap is dramatic.
This means that primary elections do not select the candidate with the broadest appeal. They select the candidate with the most intense support among a self-selected ideological minority. A candidate who speaks fluently to the committed base — who performs the right signals of loyalty, uses the right vocabulary, endorses the right myths — is at an advantage over a candidate who might appeal to a wider public but fails to excite the primary electorate.
The general election then presents the result of this filter as though it were a full democratic choice. Voters are choosing between two candidates who have already been pre-selected by processes that excluded most of them.
The radicalisation mechanism works as a ratchet — a one-way pressure that moves the system in a single direction without a corrective mechanism to pull it back.
The ratchet is structural. Each electoral cycle reinforces the previous one. Representatives who survive primaries know exactly what secured their survival — and govern accordingly.
Liz Cheney voted with the Republican Party 93% of the time during her congressional tenure — one of the highest loyalty scores in the House. She is a doctrinaire conservative, the daughter of a former Republican Vice President, and a lifelong member of the party. She broke with the party on two issues: she voted to impeach Donald Trump following the January 6th insurrection, and she refused to endorse the claim that the 2020 election had been stolen.
She was stripped of her House leadership position. She lost her 2022 Wyoming primary to a Trump-endorsed challenger by 37 percentage points.
The Cheney case is the clearest available illustration of how the purity ratchet operates. The punishment was not proportional to policy disagreement — 93% loyalty counts for nothing if the 7% includes the tribal test of the moment. What she refused was not Republican policy but Republican mythology. The distinction — between policy loyalty and narrative loyalty — is what the primary mechanism ultimately enforces.
The case is also instructive because Cheney is not a moderate. If the primary mechanism can purge a 93% loyalist for insufficient performance of tribal narrative, it can purge almost anyone. The primary does not select for ideology in the conventional sense. It selects for compliance — with whatever the base currently demands.
Primary Radicalisation is most visible in the United States, where primary elections are formalised in law and open to registered party members. But the mechanism operates wherever parties select candidates through processes dominated by their most committed members.
The mechanism varies in form — formal primary elections, party member ballots, internal conventions — but the logic is the same: when the selector is the committed base rather than the full electorate, the output is calibrated to the base, not to the country.
Primary Radicalisation is not a product of voters becoming more extreme. It is a product of the wrong voters making the key selection. The solution is not to demand more moderation from candidates — it is to change who selects them and what they are rewarded for.
Under Informed Score Voting, the primary mechanism loses its grip because its enforcement power disappears. A representative's score in the general election depends on how many voters across the full spectrum find them acceptable or admirable. Appealing only to the committed base — while alienating the rest — produces a lower overall score. The incentive reverses: a candidate who can attract marks from a wide range of voters outperforms one who maximises intensity within a narrow base.
The primary ratchet is also the enforcement mechanism for Party Over Country: primary threats are what makes the compliance machine work. Remove the primary threat — by making the general election the arena that actually matters — and party discipline over individual representatives weakens. Representatives who exercise independent judgment stop being automatically vulnerable. The ratchet loses its teeth.
This is what the shift from single-choice voting to multi-expression voting ultimately produces: elected representatives who are answerable to the full electorate rather than to the ideological fringe. Representatives rewarded for breadth, not intensity. A legislature that reflects the country rather than its most committed factions.