By Nick Bryant
BBC News, Sydney
"Twenty-one leaders, one great city."
The Apec summit is currently dominating the centre of Sydney
For weeks now, this catchy slogan has been emblazoned across newspapers and billboards in an attempt to persuade sceptical Sydney-siders that hosting the Apec (Asia-Pacific economic co-operation) summit is not such a bad thing.
But it has been a hard sell. The slogan is only a small part of the equation.
A fuller accounting brings in the 4,500 New South Wales police, 1,500 defence personnel, 450 federal police, one newly-purchased water cannon and 500 recently-vacated prison beds to accommodate all the arrested protesters.
The security bill for Apec has mushroomed to A$170m (US$140m, £70m) according to one government estimate - more than it cost to patrol the 2000 Sydney Olympics.
Then add the A$320m which business groups claim will be accrued by the decision from the New South Wales government to give Sydney a public holiday this Friday.
Diplomats and foreign reporters have converged on the city
And what of the impact on small businesses unlucky enough to be situated "behind the wire" - the rabble-resistant fence, 2.8m high and 5km (3 miles) long, which has been dubbed "the great wall of Sydney" and has disfigured one of the world's most beautiful cities.
On the positive side of the ledger, over 4,000 overseas officials and delegates will be descending on the city, wallets hopefully bulging.
And they will be watched, listened to and written about by over 1,000 members of the foreign media.
Still, many Sydney-siders are left asking: what is Apec for?
In answer to that question, it is worth remembering that the Apec forum is of the same extraction as the boomerang, the combine harvester, the black box flight recorder and the Granny Smith apple - it is an Australian invention.
Former Prime Minister Bob Hawke came up with the idea and in 1989 invited 11 countries to join him for the first summit at the Hyatt Hotel in Canberra.
The self-serving aim was not just to boost trade and economic co-operation, but to persuade Washington to accord the Asia-Pacific region a higher diplomatic priority just as the Cold War was drawing to an end.
For an international organisation to function effectively it has to be more than its sum of statistics
Mr Hawke's successor, Paul Keating, had bigger and bolder ambitions for Apec, and persuaded Bill Clinton to host the first leaders' summit in Seattle in 1993.
But it is still easy to agree with a leading Australian diplomat's famously disdainful one-liner: that the Asia-Pacific Economic Co-operation was "four adjectives in search of a noun".
Peter Hartcher, the international editor of the Sydney Morning Herald, goes further -suggesting that Apec is "21 leaders in search of an agenda".
Nobody doubts that the members of Apec have economic and diplomatic clout. This summit will bring together countries which account for 56% of the world's economy, 40% of its population and 48% of its international trade.
Apec has six out of the world's 10 largest carbon emitters and five of the world's six largest standing armies. In Indonesia, it has the world's largest Muslim nation.
But for an international organisation to function effectively, it has to be more than its sum of statistics.
Fans of the Apec model commonly cite three instances where it proved it punched its diplomatic weight.
The first came at the inaugural leaders' meeting in Seattle, which President Clinton used to help break the impasse over the stalled "Uruguay round" of international trade talks.
The second came in 1999, where the Apec summit in New Zealand helped pave the way for Australia's intervention in East Timor.
And the third happened in Vietnam, in November last year, when Apec leaders agreed to a statement condemning North Korea's nuclear test the month before.
This year in Sydney it is hard to see where a concrete diplomatic achievement anywhere near that scale will come from.
This year's end of summit photo is the subject of much speculation
Prime Minister John Howard has placed the environment at the top of the agenda, since the world's three most voracious energy consumers - China, the US and Russia - are all in attendance.
But he knows that the summit will not produce any binding targets for cutting greenhouse emissions.
Instead, he is aiming for something much less ambitious and much more diplomatically opaque: reaching a regional consensus on a post-Kyoto framework.
In reality, Australia's beleaguered prime minister is hoping to boost his green credentials ahead of an election which the polls suggesting he will struggle to win.
Much of the pre-summit hype has focussed on what the leaders will wear in their "family photo", where traditionally they don the national costume of the host country.
So far it remains a closely-guarded sartorial secret, with Mr Howard ruling out Speedo swimming trunks, or budgie smugglers as they are called here.
It is a gift to the critics of the summit. Apec 2007: One great city, 21 world leaders and a very expensive photo-opportunity.