The International Court of Justice has ruled that workers in the 151 states bound by Convention No. 87 hold a right to strike under the International Labour Organization's central freedom-of-association treaty. The advisory opinion, delivered this month at The Hague, settles a long-running interpretive dispute that has shaped global labour law since 1948.

The court issued its ruling at the request of the 187-member ILO, which asked the ICJ to clarify the scope of the 1948 Freedom of Association and Protection of the Right to Organise Convention. The single question before the court was whether the treaty silently guarantees industrial action. The answer is yes.

What did the court decide?

The ICJ held that the freedom of association Convention No. 87 protects encompasses the right of workers to withhold their labour collectively. The court treated the right to strike as an inherent feature of the freedom of association the convention guarantees, ending decades of legal uncertainty over the treaty's reach.

Although ICJ advisory opinions carry no binding force in the technical sense, they hold decisive interpretive weight for the ILO's supervisory bodies and treaty-monitoring committees. Domestic labour courts that routinely defer to those bodies will treat the ICJ's reading as the definitive interpretation of Convention No. 87.

The opinion is the ICJ's first substantive interpretation of a labour treaty, marking a shift in the court's relationship with the 1919-founded Geneva agency.

Why does the ruling matter for employers?

Multinational employers now face a narrower room to resist strike-related ILO complaints. Until now, some employer organisations argued that Convention No. 87 protected only union-formation activity, leaving industrial action outside the treaty's reach. The ICJ has rejected that reading outright.

Government lawyers should expect renewed scrutiny of national laws that restrict or ban strikes in essential services, public transport, and export-processing zones. The ILO's Committee on Freedom of Association, which examines hundreds of complaints each year, can now invoke the ICJ's reasoning directly when ruling on member-state compliance.

For companies facing strike threats in jurisdictions where industrial action remains criminalised, the decision creates fresh arguments for claimants citing international obligations. Domestic judges hearing injunction applications will weigh the new reasoning.

Why has the question lingered so long?

Convention No. 87's original text does not mention strikes. The ILO's supervisory bodies read the right into the convention through more than 75 years of decisions, but several governments and employer federations contested that interpretation at every turn.

Trade-union bodies, including the International Trade Union Confederation representing roughly 200 million workers across 162 countries, argued that strikes without enforcement are worthless. Employer organisations, led by the International Organisation of Employers, held that the 1948 drafters deliberately omitted industrial action from the text.

The conflicting readings produced years of contradictory supervisory findings, leaving national courts free to follow either interpretation. The ICJ's ruling removes that ambiguity at the top of the international legal order.

What happens next?

The ruling does not override national legislation directly. Member states retain discretion over the form strikes take, the categories of workers permitted to walk out, and procedural safeguards such as notice periods and ballot requirements.

Restrictions that nonetheless render the right to strike meaningless — outlawing sympathy action, jailing repeat organisers, or barring entire sectors from industrial action — now carry greater international-law risk. For lawyers advising on cross-border disputes, the decision offers a fresh arsenal of arguments before domestic judges, arbitral panels, and the ILO's supervisory bodies.

What does this change outside the courtroom?

Beyond litigation, the opinion sharpens the soft-power tools that labour advocates have wielded since 1948. Trade-union delegations at the ILO's annual International Labour Conference can now demand that governments justify any national carve-outs from the right to strike, using the ICJ's reasoning as the benchmark.

Its long shadow will fall on every collective-bargaining negotiation, court injunction, and government crackdown that touches the 151 states bound by Convention No. 87.