Guarantee (international law)

Guarantee – a method to ensure the fulfilment of international obligations, when a state promises to help the other state to fulfil its obligations, when some third party hinders that.

Previously other methods to ensure fulfilment of international obligations, like oaths or receiving hostages, were also called guarantees.

One example of such an obligation can be neutrality. For example, before World War I neutrality of Switzerland, Belgium and Luxembourg had been guaranteed.