What solidarity means: from Durkheim to the EU Solidarity Clause

Solidarity means standing by people who share your situation, and accepting a cost to do it. That is the core of almost every definition. The word comes from Roman law, where an obligation in solidum bound several debtors for the whole of a debt, so that the creditor could claim all of it from any one of them. French lawyers kept solidaire for that joint liability, and in the nineteenth century the word slipped out of the law courts into politics and social theory. The legal idea survives in the modern one: each member answers for the whole.

Beyond that core, different fields stress different things. The table below sets out the main senses, because a lot of confusion in debates about disaster aid comes from people using one meaning while hearing another.

Social solidarity and Durkheim’s two kinds

The modern sociological meaning was shaped above all by Émile Durkheim. In The Division of Labour in Society, published in French in 1893 as De la division du travail social, he asked what holds a society together once people no longer share the same work, beliefs and way of life.

His answer distinguished two forms of social solidarity.

Mechanical solidarity binds people through likeness. In small, relatively undifferentiated societies, members do similar work, hold the same beliefs and share what Durkheim called the collective conscience. The bond is strong because everyone resembles everyone else, and an offence against shared norms is felt as an offence against all. Durkheim saw this reflected in law that is mainly repressive: it punishes.

Organic solidarity binds people through difference. As the division of labour advances, individuals specialise and come to depend on each other, much as the organs of a body each do a different job and none can survive alone. The bond here is interdependence rather than resemblance. Durkheim saw it reflected in law that is mainly restitutive, such as contract and commercial law, which aims to restore relationships instead of punishing transgressions.

Durkheim did not think the transition was smooth. He described abnormal forms of the division of labour, including an anomic form in which the rules governing relations between specialised functions fail to keep up, and a forced form in which people are pushed into roles that do not match their abilities. Both produce conflict instead of cohesion.

The distinction is useful well beyond nineteenth-century sociology, and disasters make it easy to see. The neighbours who shovel mud out of each other’s cellars after a flood are acting on something close to mechanical solidarity: they belong to the same place, share the same misfortune and help because they are alike. The insurance pool that pays for the repairs, such as Spain’s Consorcio de Compensación de Seguros, works on organic solidarity. The policyholder in Seville and the policyholder in Valencia have never met and share nothing except a contract with the same institution, yet each depends on the other’s premiums. Modern disaster policy is largely an effort to build organic solidarity strong enough to carry losses that no village could carry alone. That reading is this article’s application of Durkheim, not his own example; he wrote before catastrophe insurance existed in its modern form.

A side note that rarely makes the textbooks: Durkheim’s own interest in solidarity was partly practical. He was writing in a France where politicians such as Léon Bourgeois, whose book Solidarité appeared in 1896, were turning the word into a programme for social insurance. The sociology and the politics fed each other, and historians of ideas still disagree about how much.

Solidarity between states

When the word moves into diplomacy, it changes again. Between states, solidarity usually means a commitment to assist one another that goes beyond what a narrow calculation of interest would require, but not so far beyond that governments cannot justify it at home.

The commitment is rarely unconditional. Three tensions recur:

• Sovereignty. A state asking for help must let foreign teams, aircraft or auditors onto its territory. Many governments hesitate, and some prefer to cope alone.
• Reciprocity. Solidarity is sold to voters as insurance: help given now earns help later. Countries that expect never to need help are less enthusiastic, a tension explored further in the piece on the importance of solidarity.
• Moral hazard. If neighbours will always pay, a government has less reason to invest in flood defences or to require its citizens to insure. This argument is made most loudly by net contributors to any common fund.

The European Union is the place where these tensions have been written down most explicitly. Article 2 of the Treaty on European Union describes the Union’s values as common to the Member States “in a society in which pluralism, non-discrimination, tolerance, justice, solidarity and equality between women and men prevail”, and Article 3 commits the Union to promote “economic, social and territorial cohesion, and solidarity among Member States”. Those are statements of principle. The operational version is elsewhere.

The EU solidarity clause: Article 222 TFEU

Article 222 of the Treaty on the Functioning of the European Union, in force since the Lisbon Treaty, is known as the solidarity clause. Its first sentence reads: “The Union and its Member States shall act jointly in a spirit of solidarity if a Member State is the object of a terrorist attack or the victim of a natural or man-made disaster.”

The rest of the article spells out what that means. The Union “shall mobilise all the instruments at its disposal, including the military resources made available by the Member States”, to prevent terrorist threats, protect democratic institutions and civilians, and assist a Member State on its territory, at the request of its political authorities, in the event of a terrorist attack or a natural or man-made disaster. The other Member States shall assist it at that request and coordinate between themselves in the Council.

Three features stand out:

1. It is triggered by the affected state. Help follows a request from that country’s political authorities. Solidarity here respects sovereignty first.
2. It covers disasters explicitly. Floods, earthquakes and industrial accidents sit in the same article as terrorism, which tells you how seriously the drafters took them.
3. It needs machinery. The treaty left the details to a Council decision, adopted on 24 June 2014 as Decision 2014/415/EU, which ties the clause to existing instruments instead of creating new ones.

The solidarity clause is often confused with Article 42(7) of the Treaty on European Union, the mutual assistance clause, which concerns armed aggression and belongs to defence policy. The two were designed to complement each other: one for wars, one for disasters and attacks.

How the idea becomes concrete in disaster policy

A treaty article does not pump water out of a basement. Solidarity becomes real through instruments that have staff, budgets and procedures. In the EU there are four that matter most for natural disasters.

The Union Civil Protection Mechanism, set up in October 2001, lets a country overwhelmed by a disaster ask for help through the Emergency Response Coordination Centre in Brussels. According to the Commission’s civil-protection department, it had been activated more than 880 times since 2002, 64 times in 2025 alone, and includes ten participating states outside the EU, from Norway and Iceland to Türkiye and Ukraine. When Belgium asked for help during the July 2021 floods, a French rescue team and helicopter were mobilised the same day.

The European Civil Protection Pool, established in 2013, is the pre-committed part of that system. Member and participating states register response teams and equipment in advance, which are tested in exercises and certified. As of September 2025 there were 153 such resources, of which 118 were certified.

rescEU, created in 2019, goes a step further: assets financed entirely by the EU, including firefighting planes and helicopters, a medical evacuation plane and stockpiles of medical and CBRN equipment. It is the closest thing the EU has to a common fire brigade.

The EU Solidarity Fund, created in 2002, is the financial arm. It pays part of the public cost of emergency and recovery operations after a major or regional natural disaster. It only supports public operations and covers non-insurable damage; it does not compensate private losses. The Commission’s regional policy department says it has mobilised over €9.6bn for 110 natural disasters and 20 health emergencies. The detailed rules, thresholds and largest grants are covered in the piece on EU solidarity in disasters, and the national arrangements that do most of the paying are compared in the schemes overview.

Each instrument embodies a slightly different meaning of solidarity. The Civil Protection Mechanism is solidarity as mutual help between equals, close to the diplomatic sense. The Pool and rescEU are solidarity as shared capacity, the organic kind in Durkheim’s terms. The Solidarity Fund is solidarity as a transfer, closer to the social-policy sense: richer and luckier states paying towards the costs of poorer or unluckier ones.

When the meaning is tested

The test of any definition is what happens when it is applied. Two findings from official reviews show the gap between the principle and the practice.

In 2008 the European Court of Auditors examined whether the Solidarity Fund was rapid, efficient and flexible. It found that the fund “did not provide a rapid response”: the time between application and payment was usually about one year. Yet the same report found that the states receiving money were satisfied or very satisfied, and concluded that the fund had met its underlying objective of demonstrating solidarity with Member States in times of disaster. Solidarity, on that reading, is as much a signal as a sum of money.

The second finding concerns who asks. The Commission’s proposal of 27 August 2024 for aid after the 2023 disasters records that Italy requested assistance through the Civil Protection Mechanism for the May 2023 floods in Emilia-Romagna, while Greece did not request it for Storm Daniel in Thessaly. Both received money from the Solidarity Fund. The clause that makes help conditional on a request also leaves each government free not to ask, and some prefer not to. The protection gap explains how much of the loss in both countries was never insured at all, which is the larger part of the story.

Greece’s grant for Storm Daniel came to €101.5m, against €2.33bn of direct damage recorded in the Commission’s proposal. Italy’s for Emilia-Romagna was €378.8m, plus €67.8m for Tuscany, against €8,533m of declared damage.