Every coalition government carries the seeds of its own destruction, and the germination follows a remarkably consistent pattern. The drama of political collapse—the midnight negotiations, the tearful press conferences, the accusations of betrayal—obscures a mechanical process as predictable as metal fatigue. Junior partners face an existential paradox: they must claim credit for popular policies while their senior partner absorbs most of the glory, yet they cannot escape blame for unpopular ones. This asymmetry is not a bug in coalition governance; it is the defining feature.
The lifecycle typically spans three phases. In the honeymoon period, partners paper over ideological differences with vague language and shared enthusiasm for power. The middle phase sees junior parties hemorrhage support to opposition forces who can criticize without consequence. The terminal phase arrives when those junior partners calculate that the electoral cost of remaining exceeds the reputational cost of bringing down the government. At that moment, some minor policy dispute—often genuinely trivial—becomes the pretext for withdrawal.
The junior partner death spiral
Political scientists call it the "cost of governing," and the data across decades of European elections is unambiguous: junior coalition partners lose an average of several percentage points of their vote share while in government. The Free Democrats in Germany have experienced this repeatedly, watching their support erode during coalition participation before rebuilding in opposition. The Liberal Democrats in Britain were nearly annihilated after their coalition with the Conservatives, losing the vast majority of their parliamentary seats. The pattern holds regardless of policy success because voters attribute achievements to the prime minister's party while blaming the coalition as a whole for failures.
This creates perverse incentives. Junior partners must differentiate themselves to survive, which means publicly opposing their own government's policies. But excessive differentiation undermines the coalition's coherence and credibility. Too little differentiation, and they become indistinguishable from their senior partner—at which point voters reasonably conclude they might as well vote for the original. There is no stable equilibrium.
The confidence game
Parliamentary systems require governments to maintain the "confidence" of the legislature, a term that sounds psychological but operates mechanically. A government that loses a confidence vote must resign or call elections. This gives every coalition partner a nuclear option: threaten to withdraw support and collapse the government unless demands are met. The threat is most credible when the threatening party has least to lose—typically when their poll numbers have already cratered and early elections seem preferable to continued decline.
Italy has elevated this to an art form, cycling through dozens of governments since the Second World War. The Italian system combines proportional representation, which fragments the legislature, with a political culture that treats government collapse as a negotiating tactic rather than a crisis. Israeli politics operates similarly, with small religious or nationalist parties extracting extraordinary concessions by threatening to bring down governments over issues affecting tiny fractions of the population.
Why some coalitions survive
Grand coalitions between major parties—like Germany's periodic partnerships between center-left and center-right—prove more durable precisely because both partners have too much to lose from collapse. Neither can credibly threaten to walk away when doing so would benefit only the extremes. But grand coalitions carry their own pathology: they hollow out the political center by leaving no mainstream opposition, driving frustrated voters toward fringe parties. Germany's Alternative für Deutschland grew partly in the vacuum created by grand coalition governance.
The coalitions that endure tend to share either deep ideological alignment or a common external threat that makes internal disputes seem petty. The latter explains why wartime coalitions hold together despite enormous policy disagreements: the cost of failure is too visible to ignore.
Our take
Coalition instability is not a failure of political will or leadership character—it is the rational outcome of structural incentives that punish cooperation. Reformers who propose coalition-friendly electoral systems should understand they are also proposing coalition-fragile governments. The trade-off between representativeness and stability is real, and no clever institutional design eliminates it. Countries get to choose their dysfunction: the artificial majorities of first-past-the-post systems or the negotiated paralysis of proportional ones. Pretending otherwise is the only true political naivety.
