A voluntary association...
The Commonwealth has no charter and membership is entirely voluntary. And of nations eligible to join, very few chose not to do so. This distinguishing characteristic has been of considerable historic importance: when countries had recently achieved their independence from the UK, it was important for them to stress the change in their relationship, from dependent status to equal partnership. The emphasis on equality has helped the association to play leading roles in decolonisation, combating racism and advancing sustainable development in poor countries.