International courts rely on the principle of military necessity. Under Additional Protocol I of the Geneva Conventions, an object becomes a legitimate target if it makes an "effective contribution to military action." For a pipeline, this requires more than proof that the energy sales fund a government's budget.
Economic coercion rarely meets this threshold on its own. Using gas as a political lever is a diplomatic strategy. To justify a strike, courts would need evidence that the infrastructure serves a dual-use purpose, where the energy flow is an indispensable link in the logistics of active combat operations.
Proportionality dictates the final ruling. If destroying a pipeline causes mass civilian freezing or starvation, the expected military advantage must be immense. Courts would likely demand a direct and immediate link between the energy supply and a specific military capability, such as powering a dedicated weapons facility or a mobilization hub.
Without this concrete functional link, the infrastructure remains a civilian object. Broad claims about "economic warfare" typically fail to override the protected status of civilian utilities in IHL.