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.
The Policy Pendulum swings on the scale of electoral cycles: four years, eight years, the same policies reversed and reinstated in a do-undo-redo rhythm. The Realignment Trap is the same pendulum at generational scale. One swing takes decades. The motion is real — parties collapse, coalitions transform, the ideological landscape appears redrawn. But when the oscillation completes, the binary has reconstituted around new poles. The system is equally broken. The clock is simply set differently.
The duopoly that single-choice voting produces is not stable. It is structurally inevitable — but its specific contents are not. The two dominant camps change over time as social forces, demographic shifts, and political failures accumulate. When the pressure becomes acute enough, the party system undergoes a realignment: an established party collapses, a new movement rises, the old tribal identities dissolve and reconstitute around new poles.
These realignments are real. The parties change, the coalitions change, sometimes the entire ideological axis of politics shifts. And yet the outcome is always the same: within a cycle or two, two dominant camps reassert themselves — different faces, different names, identical structure. The trap is not that nothing changes. It is that the one thing that would actually cure the disease — the voting method — never changes. Everything else reshuffles. The binary survives.
Realignments produce two structural variants. In the first, established parties are replaced wholesale: a previously marginal party rises to take one of the two dominant positions, displacing its predecessor. In the second, the established parties remain but undergo such radical internal transformation that their policies, base, and leadership bear little resemblance to what they were a generation earlier. Both variants produce the same result: the binary reconstitutes.
The reconstitution is not a coincidence. It is a structural inevitability, and it follows from a simple cause: the voting method has not changed. Whatever the new coalition is, it must compete in a system that funnels every shade of political opinion into exactly two opposing camps — and treats anything that refuses to fit as a spoiler. The spoiler effect — the mechanism by which voting for a third party helps elect the one you like least — remains operative. Strategic logic reasserts itself. Voters who supported the insurgent movement calculate that splitting the vote will elect their enemy. The insurgent movement, facing the same arithmetic, consolidates. The binary is reconstructed from within.
The realignment's promise — that this new movement will break the two-party monopoly — cannot be delivered by a new party alone. It requires changing the underlying election rules. Without Informed Score Voting or at minimum Approval Voting, any new party faces the same spoiler dynamics that destroyed every previous third-party challenge. The energy of the realignment is absorbed by the system and converted back into a binary. The trap closes.
Political scientists have divided the history of the American two-party system into successive party systems — eras defined by a stable alignment of parties, coalitions, and issues, each ending in a realignment that reshuffles the elements without escaping the binary:
Six realignments across two centuries. One persistent structure.
The French presidential election of 2017 appeared to shatter the established binary entirely. Emmanuel Macron's La République En Marche collapsed both the Socialist Party and Les Républicains — the two parties that had alternated in power for decades — into near-irrelevance within a single election cycle. The old left-right divide seemed dissolved.
Within one cycle, a new binary had reconstituted: Macron's centrist bloc versus Marine Le Pen's Rassemblement National. The traditional parties were gone. The faces were new. The structure — two opposing camps, one of which must win — was identical. The trap had closed faster than in any previous modern realignment.
The Liberal collapse (1906–1935). Britain's most dramatic realignment unfolded between the two world wars. For a century, the Conservative-Liberal binary had governed British politics. The Liberal Party was not a fringe movement — it had produced Gladstone, Lloyd George, and the great reforming government of 1906. Then Labour emerged to compete for the same voters, and the spoiler logic of single-choice voting did its work. As Labour grew, voting Liberal helped elect Conservatives. The Liberal vote bled away. Within two decades, the Conservative-Liberal binary had been replaced by the Conservative-Labour binary. The Liberals did not gradually decline — they were displaced from the left-camp slot. The binary reconstituted around a new pole.
The SDP Alliance (1983). In 1981, four senior Labour figures — the "Gang of Four" — broke away to form the Social Democratic Party, allying with the Liberals in a formal electoral pact. The 1983 election seemed to confirm the realignment's promise: the SDP-Liberal Alliance won 25.4% of the national vote, barely two percentage points behind Labour. It returned 23 seats. Labour, with marginally more votes, returned 209. The promise of a broken binary had produced one of the most severe disproportionalities in British electoral history. The Alliance eventually merged into what became the Liberal Democrats. The binary absorbed the disruption and reconstituted. The trap had closed, again, in plain sight.
The PC collapse (1993). The 1993 Canadian federal election produced one of the most spectacular single-election collapses in democratic history. The governing Progressive Conservative Party, which had won 156 seats four years earlier, was reduced to two. The right fractured: the Reform Party, a western populist insurgency, rose to fill part of the vacuum; the rump Progressive Conservatives persisted as a separate party. For a decade, the right-of-centre vote split between two parties, handing sustained Liberal majorities to a centre-left party that had not radically changed. The realignment appeared total.
The Conservative merger (2003). By 2003, the Canadian Alliance — the Reform Party's successor — and the Progressive Conservatives merged to form the Conservative Party of Canada. The right-camp slot, emptied in 1993, had been refilled. The binary reconstituted within ten years. The faces were different, the regional coalition was different, the policy emphasis had shifted. The structure was identical: two dominant camps, one of which must win, spoiler logic making anything else untenable. The Realignment Trap had closed on schedule.
The Realignment Trap is perhaps the most demoralising symptom in the Duverger Syndrome — not because it prevents change, but because it weaponises hope. Each realignment arrives with a genuine emotional charge. The new movement feels like a genuine departure from the entrenched binary. Voters who have disengaged from or grown cynical about the old parties invest in the new possibility: the new party, the insurgent candidate, the movement that promises to break the mould.
When the binary reconstitutes — as it must, structurally — that emotional investment becomes a source of cynicism that is harder to recover from than the original disengagement. The voter who has been through multiple realignment cycles carries a well-founded scepticism. The trap teaches voters not to hope. And democratic health depends on hope.
This produces a compounding problem across generations. Each realignment trap deposits another layer of disillusionment into the political culture. The cumulative effect is a citizenry that has learned — from experience, not from cynicism alone — that the system will absorb any challenge and reconstitute the binary. That learning is correct. It is also fatal to the sustained engagement that democracy requires.
The Realignment Trap is frequently misread as evidence that the system is self-correcting — that when democratic dysfunction becomes severe enough, the electorate produces a corrective. This is the wrong reading. The correct reading is the opposite.
Realignments release pressure without solving the underlying problem. The energy and anger that might otherwise be directed at electoral reform — at changing the voting method itself — is channelled into building the new movement, electing the new faces, fighting within the new binary. The realignment is the system's defence mechanism against structural change. It provides the appearance of transformation while preserving the structure that produces dysfunction.
The cure is not a better realignment. Every realignment since the Whig collapse has promised to break the binary. None has. The cure is changing the voting method — because the binary is not produced by the parties, by the voters, or by the specific political moment. It is produced by the arithmetic of single-choice voting. Change the arithmetic, and the structural pressure toward dualism disappears.
Under Informed Score Voting, the strategic logic that forces realignments back into a binary is broken at the root. A voter can express genuine enthusiasm for the new movement without penalising the established party they still prefer over the opposition. A new party can build support without triggering the spoiler calculation that forces consolidation. The insurgent does not face a binary choice between staying marginal and merging.
The result is that genuine pluralism becomes stable, not just temporarily possible. New movements can emerge, find their level, and persist — without being absorbed into a binary or destroyed by the spoiler effect. The realignment trap requires the trap mechanism to function: the moment voters can express multi-candidate preferences, the mechanism fails. The trap opens. The binary stops being inevitable.
What the history of realignments shows, above all, is that the energy for change has never been the problem. Every realignment represents a genuine mobilisation of voters who wanted something different. The problem is that all that energy has been channelled into a container — the binary — that converts it back into the same structure. Informed Score Voting changes the container. The energy, finally, has somewhere to go.