When people want different things, the reflex is to treat it as a war to win or a pie to split. But most stand-offs are only zero-sum on the surface: look behind each position to the need beneath it, and a larger option can often satisfy everyone. Solidarity is the discipline of finding those win-wins — and, more durably, of building an ecosystem where the cooperative move is also the easiest one.
Traffic is safer not because each driver is a saint, but because roads, signs, and rules make safe driving easier than reckless driving.
Even perfect local care fails in a hostile wider ecosystem. Solidarity equips the field so that civic behaviour wins by design.
Tronto's fifth phase asks whether care is consistent with democratic commitments to justice, equality, and freedom for all. For Civic AI, solidarity asks a structural question: do the rules of the ecosystem make cooperation easier to practise than domination?
There is a technical reading of that question. Standard multi-agent reinforcement learning optimises a simple sum of per-agent rewards — which is why systems built on it reliably produce polarisation, engagement-maximisation, and the collapse of the commons. Solidarity, formally, is what cannot be written as a sum over individuals: a population-level pressure toward shared meaning that no single agent can satisfy — only the group can. Not a settled result; but on this reading, a Civic AI architecture that omits such a term is not just politically lonely — it is technically incomplete.
Definition
- Identity without exposure. Agent IDs should prove that an agent answers to a real steward without publicly exposing private details — selective disclosure, or meronymity: proving role without revealing person. Accountability should not require doxxing.
- Interoperability beats captivity. Portability and open protocols move competition to quality of care. Exit rights protect freedom by making it possible to leave without losing your audience or history. Utah's Digital Choice Act — which requires social networks to forward a user's likes, followers, and social graph when they migrate to a new platform — points the way.
- Federation over monoliths. Share threat intelligence without a single chokepoint. Local policies stay local, but defence compounds across institutions.
- Expression is not amplification. Recommender accountability is a civic duty. Ranking in civic contexts should reward cross-group reason-giving and shared problem-solving, not only whatever inflames one cluster fastest.
Why it matters
Local repair is fragile if the wider infrastructure rewards lock-in, opacity, and outrage. A system can be attentive, responsible, competent, and responsive inside one deployment while still being trapped in a hostile market or protocol environment.
Solidarity means no one gets a structural exemption from caring. Tronto's metaphor: "The first thing we need to do is collect all of those free passes out of taking care responsibilities seriously." For AI systems, the equivalent passes are: "we're too big to regulate," "users consented in the ToS," "we opened the weights," and "we donated to safety research." Solidarity collects these passes by making cooperation structurally unavoidable.
Solidarity is where the framework becomes democratic infrastructure. It asks whether justice, equality, freedom, plurality, and mutual accountability are easier to practise because of the ecosystem, or in spite of it.
Open stacks and anti-rival resources
What made Carnegie's 2,500-plus public libraries democratising was not the buildings but the open stacks: patrons browsing the shelves themselves rather than petitioning a librarian to fetch on their behalf. Vertical AI platforms that hold capability behind proprietary APIs reproduce the closed-stack model; open-weight models, open protocols, and community-maintained evaluation registries are the open-stack equivalent — infrastructure that treats communities as capable actors, not consumers to be served on the platform's terms.
Knowledge, unlike oil, is anti-rival: use enriches rather than depletes it. The same holds for open protocols — eduroam grows more valuable for every member as institutions join, with no participant capturing the gain. A solidarity-equipped ecosystem works the same way: when one city adopts selective-disclosure attestations, every other city can adopt the standard at near-zero marginal cost. None of this emerges spontaneously; it takes law as infrastructure — interoperability-as-public-good legislation of which Utah's Digital Choice Act is a working prototype. Solidarity is where the individual care loop connects to the commons.
What it looks like in practice
- Selective-disclosure identity. Agents, organisations, and people have verifiable attestations held by trusted custodians; public proofs stay minimal, but challenge and revocation remain real.
- Social portability. Users export social graph and content, pass interoperability tests, and keep personal audiences when leaving. Freedom becomes practical because exit no longer means social exile.
- Bridge audits. Platforms publish a bridge index — a public measure of cross-group participation and co-endorsement in shared decisions. Plurality becomes visible instead of being left to branding claims. The index is not a substitute for genuine pluralism; it is a diagnostic that makes genuine pluralism harder to fake.
- Federated safety network. Partners detect harms in their own cultural context, share threat signals, and keep enforcement local rather than ceding everything to one hub.
- Protocol-level norms. Machine-readable terms of cooperation set common duties: no scraping without consent, honour appeal webhooks, respect exit.
From ideas to practice
- Stand up an identity custodian. Set up community orgs or public interest entities to issue and hold attestations; publish revocation and challenge endpoints.
- Mandate portability in procurement. Public buyers require protocol interop and exit-with-trust drills.
- Adopt bridge audits. Ensure platforms publish relational health metrics quarterly; have third parties verify.
- Join a safety federation. Contribute to and consume from a shared threat registry; localise enforcement.
- Default to civic ranking rules. In civic contexts, make feeds reward reason-giving, contestability, and cross-group cooperation rather than outrage.
Buildable tools
- Agent identity schema for selective disclosure, revocation lists, and proof formats.
- Portability harness for export/import scripts and fidelity checks.
- Bridge audit kit to compute and publish cross-group participation metrics.
- Federated safety hub with open APIs for threat intelligence and local adapters.
- Shared cooperation rules that agents and platforms can verify automatically.
One case: the flood-bot
The crisis deepens — and the community has renamed the bot the River-Steward: an attentive, bounded agent stops looking like a product and starts looking like a neighbour.
- Identity. Scammers begin impersonating aid workers to intercept funds, while real volunteer translators face harassment from stressed, displaced claimants. The city shifts to selective-disclosure IDs so translators can prove their role without exposing personal phone numbers. Abuse drops; accountability rises.
- Portability. Procurement rules require case files, consent records, and contacts to move from the emergency bot to long-term housing services in one export rather than being typed in again.
- Federated defence. Scam reports from neighbouring cities flow in via the safety network; the bot downgrades suspect links by default.
- Bridge audit. A weekly public bridge index shows whether renters and homeowners are co-endorsing more shared remedies than at launch.
What could go wrong
- ID creep. IDs become dossiers. Fix: Selective disclosure by design; minimal proofs; independent custodians; strong revocation.
- Portability theatre. Exports are unreadable or lossy. Fix: Exit tests in contracts; penalties for fidelity failure.
- Federation capture. One big player dictates norms. Fix: Polycentric governance; open standards; rotating stewards.
- Federation as attack surface. Without security hardening, a network of local agents becomes a distributed botnet waiting to be recruited. Fix: Mandate sandboxing, least-privilege execution, and input validation at every node (Pack 3); federated security audits; shared vulnerability disclosure.
Interfaces
- From Responsibility (Pack 2): portability and exit clauses are referenced in every engagement contract.
- From Responsiveness (Pack 4): repair culture feeds trust across organisations.
- To Symbiosis (Pack 6): solidarity provides the treaties local agents need to cooperate.
A closing image: the well-marked interchange
Imagine a well-marked interchange — many lanes, clear signs, safe merges — not a place where each driver is a better person, but one designed so that cooperative driving is the easiest thing to do. That is what solidarity builds: not a higher standard of individual virtue, but a road worth being virtuous on.
