The problem of Zimbabwe has been a major test of the democratic values to which the Commonwealth has committed itself.
Robert Mugabe is defiant
Ironically, it was in the Zimbabwe capital of Harare in 1991 that the commitment to democracy and the rule of law among its member states was proclaimed.
Until then, the principle had been one of non-intervention. Under those rules, it was not uncommon for coups to take place and for the latest general or dictator to show up at the next heads of government meeting.
These days, the Commonwealth probably has relevance only because it has changed course.
"This is the first time in the Commonwealth that there has been a suspension without a coup preceding it," said Tim Shaw, director of the Institute of Commonwealth Studies at the University of London.
"It shows that the Commonwealth is prepared to go over the fine line beyond which certain practices are not acceptable," he told BBC News Online.
"It was the right call," Mr Shaw said.
"The Commonwealth may be a marginal player but Mugabe's anger shows that it got under his skin. Frankly there is no point in talking to him. There are few levers left. He is an injured bull."
The decision by the Commonwealth to continue the suspension of Zimbabwe from formal meetings led to an announcement from President Mugabe that his country would leave the group of mainly former British territories completely.
Attachment to democratic values
The Commonwealth action came with the price tag of divisions between its members. A southern Africa group, led by South Africa, pressed for Zimbabwe to return to full membership but in the end an alliance between the so-called "White Commonwealth" of Britain, Canada, Australia and New Zealand and African, Caribbean and Asian members prevailed.
The balance which the Commonwealth tries to maintain between asserting values of good governance without telling member states what to do, too much swung in favour of keeping Zimbabwe at arm's length.
The anger in southern Africa will no doubt persist. The memory of Robert Mugabe as the freedom fighter who overthrew the white minority regime of Ian Smith remains strong.
But the attachment of some of the Commonwealth's smaller countries, especially those in the Caribbean and increasingly in Africa, to democratic values cannot be underestimated either.
Another test will come over the membership of Pakistan.
Pakistan, which left the Commonwealth in 1972 and rejoined in 1989, was suspended in 1999 after the coup by General Pervez Musharraf.
It has since held parliamentary elections and there is talk about its suspension being lifted.
Problem of failing states
But if this is done in too much of a rush, those supporting Pakistan could be accused of double standards. Britain and Australia see in Pakistan an ally in the war against Osama bin Laden.
Zimbabwe also highlights the problem of how to deal with a country which is regarded as a rogue or failing state.
"It is the question of how you punish the regime and support the people at the same time," said Mr Shaw.
"I hope that the unofficial Commonwealth which helps to develop civil society in all kinds of ways will continue its work," he said.
However, Zimbabwe also faces expulsion from the International Monetary Fund, which will further affect its development.
The IMF has started "compulsory withdrawal procedures" over Zimbabwe's failure to pay its arrears. These amount to $273m.
According to IMF figures, the Zimbabwe economy contracted by 40% between 1999 and 2003 and inflation in October this year was at 526%.
The Commonwealth decision may also embolden the European Union to tighten up its sanctions. These include restrictions on travel to the EU by leading figures in the Zimbabwe government, though France caused a stir when it permitted Mr Mugabe to attend an African conference nonetheless.
No stranger to strife
Over the years, there have been many times when the obituary of the Commonwealth was about to be published.
Despite its impressive sounding statistics (53 members now, with the withdrawal of Zimbabwe, 30% of the world's population), it has little economic clout. Many members are desperately poor.
But somehow it has kept going. At the very least it gives its members a window on a wider world.
It survived fierce arguments over sanctions on South Africa, with Mrs Thatcher very much isolated.
It has also survived quite a number of comings and goings.
South Africa, then under the architect of apartheid Hendrik Verwoerd, left in 1961 and did not return until 1994.
Fiji left in 1987 after a coup. It then came back, only to be suspended after another coup attempt before returning again.
Nigeria, the host of this year's summit, was itself suspended in 1995 because of military rule and came back to full membership only four years ago.
It is a club which those out of favour later like to rejoin.
Mozambique even joined despite having had no connections to the old British empire.
The expectation must be therefore that one day Zimbabwe too will come back.