The end of the Second World War and the establishment of the United Nations caused fundamental changes in international law. Today, lawyers and politicians often talk of a ‘international community’ that co-operates to pursue global interests that are not possible for single states to achieve alone. These include the protection of human rights, environmental challenges and a wide range of issues of common concern.

The study of international law, also known as public international law, encompasses agreements and norms that govern the relations between sovereign states and their citizens and subjects. It is distinguished from private international law which deals with controversies between individuals or between private entities that have a significant relationship to several nations.

Unlike domestic or national laws, international law is not set down in legislation approved by a parliament. Instead, it is derived from a wide variety of sources including treaties, customary law, agreed-upon general principles of law (such as behaving in good faith) and judicial decisions. It is reinforced by a system of mutual respect amongst nations and the understanding that non-compliance may lead to sanctions and possibly retaliation by other states.

The International Court of Justice (ICJ) is the principal judicial organ of the United Nations. It settles legal disputes submitted to it by States and gives advisory opinions on questions of international law referred to it by authorized UN organs and specialized agencies. The ICJ’s members are elected for nine-year terms on the basis of universality, impartiality and independence.