Criteria
The criteria for membership of the Commonwealth of Nations have developed over time from a series of separate documents. The Statute of Westminster 1931, as a fundamental founding document of the organisation, laid out that membership required dominionhood. The 1949 London Declaration ended this, allowing republican and indigenous monarchic members on the condition that they recognised King George VI as "Head of the Commonwealth". In the wake of the wave of decolonisation in the 1960s, these constitutional principles were augmented by political, economic, and social principles. The first of these was set out in 1961, when it was decided that respect for racial equality would be a requirement for membership, leading directly to the withdrawal of South Africa's re-application (which they were required to make under the formula of the London Declaration upon becoming a republic). The 14 points of the 1971 Singapore Declaration dedicated all members to the principles of world peace, liberty, human rights, equality, and free trade.
These criteria were unenforceable for two decades, until, in 1991, the Harare Declaration was issued, dedicating the leaders to applying the Singapore principles to the completion of decolonisation, the end of the Cold War, and the end of apartheid in South Africa. The mechanisms by which these principles would be applied were created, and the manner clarified, by the 1995 Millbrook Commonwealth Action Programme, which created the Commonwealth Ministerial Action Group (CMAG), which has the power to rule on whether members meet the requirements for membership under the Harare Declaration. Also in 1995, an Inter-Governmental Group was created to finalise and codify the full requirements for membership. Upon reporting in 1997, as adopted under the Edinburgh Declaration, the Inter-Governmental Group ruled that any future members would "as a rule" have to have a direct constitutional link with an existing member.
In addition to this new rule, the former rules were consolidated into a single document. These requirements are that members must accept and comply with the Harare principles, be fully sovereign states, recognise King Charles III as head of the Commonwealth, accept the English language as the means of Commonwealth communication, and respect the wishes of the general population with regard to Commonwealth membership. These requirements had undergone review, and a report on potential amendments was presented by the Committee on Commonwealth Membership at the 2007 Commonwealth Heads of Government Meeting. New members were not admitted at this meeting, though applications for admission were considered at the 2009 CHOGM.
New members must "as a general rule" have a direct constitutional link to an existing member. In most cases, this is due to being a former colony of the United Kingdom, but some have links to other countries, either exclusively or more directly (e.g., Bangladesh to Pakistan, Samoa to New Zealand, Papua New Guinea to Australia, and Singapore to Malaysia). Mozambique, in 1995, was the first country to join without such a constitutional connection, leading to the Edinburgh Declaration and the current membership guidelines.
In 2009, Rwanda, formerly under Belgian and German rule, joined. Consideration for Rwanda's admission was considered an "exceptional circumstance" by the Commonwealth Secretariat. Rwanda was permitted to join despite the Commonwealth Human Rights Initiative (CHRI) finding that "the state of governance and human rights in Rwanda does not satisfy Commonwealth standards", and that it "does not therefore qualify for admission". The CHRI commented that: "It does not make sense to admit a state that already does not satisfy Commonwealth standards. This would tarnish the reputation of the Commonwealth and confirm the opinion of many people and civic organisations that the leaders of its governments do not really care for democracy and human rights, and that its periodic, solemn declarations are merely hot air."
In 2022, the former French territories of Togo and Gabon joined the Commonwealth.