Contacts
Research Political Sciences

Bending the Iron Law: Sharing Power Inside Political Parties Can Actually Help Them Win

, by Andrea Costa
New research challenges the long-standing idea that political parties must concentrate power to function — and shows why internal democracy might be their secret weapon

For decades, scholars of political organization have accepted a rather pessimistic principle: the so-called Iron Law of Oligarchy. This theory holds that all political parties, no matter how internally democratic in their early years, tend to centralize power in the hands of a few leaders. Internal democracy, from this perspective, is less a sustainable ideal and more a temporary illusion.

But a new study by Giovanna M. Invernizzi (Department of Social and Political Sciences, Bocconi University) and Carlo Prato (Columbia University) and published in the American Journal of Political Science argues that the Iron Law is not always inescapable destiny. According to their research, political parties don’t always evolve toward centralized power structures. In fact, sometimes it’s more effective for them to share power among internal factions — especially if they want to win elections.

Why internal power sharing works

Inside every political party are factions–sub-groups with their own priorities, goals, and probably their own internal passive-aggressive email chains. These factions play a critical role in helping the party reach voters, organize campaigns, and build support. But motivating them to work hard isn’t always easy.

If all the power and perks go to the winning faction (leadership positions, funding, control over policy, the backroom where decisions get made), then the losing factions have no reason to try. Why campaign hard if you’ll get nothing in return?

Invernizzi and Prato show that sharing resources more evenly among factions can motivate everyone to contribute, boosting the party’s overall chances in elections. It’s like a team sport: people play better when there’s something in it for them, even if they’re not the star striker.

When power sharing makes sense

Using a game-theory model, the study finds that internal power sharing is most likely — and most useful — under specific conditions:

  • High-stakes elections: If the electoral system is more “winner-takes-all” (like majoritarian systems), it’s riskier to rely on a single faction. Sharing power keeps everyone involved.
  • Smaller parties: These parties tend to be more vulnerable, so they’re more likely to rely on internal unity to survive.
  • Better monitoring of contributions: Systems where it’s easier to track who’s doing the work (like preferential voting) make it easier to reward factions fairly — which makes power-sharing more attractive.
  • Multi-dimensional ideological differences: When factions disagree about more than just one issue, sharing influence across issues can keep them from walking out the door.

Breaking the iron law (gently)

The paper doesn’t say that the Iron Law is false. Rather, it argues that it only operates under certain conditions: sometimes oligarchies are inevitable. Sometimes, political organizations can organize around more egalitarian principle and still be electorally competitive. Internal democracy, then, isn’t just an idealistic aspiration; it can be a vote-winning tool.

This flips the script on the usual narrative about political parties. Sometimes, a bit of internal contestation is what keeps the whole structure from falling apart. Parties that find smart ways to distribute power internally without drifting into chaos may actually perform better at the ballot box.

Implications for real-world politics

This research helps explain why some parties seem more democratic and decentralized, while others operate more like monarchies. It also gives voters (and scholars) a better way to assess how party rules shape outcomes — not just for leadership selection, but for everything from policy agendas to campaign effectiveness.

Research