Gathering in Agadir, Morocco, the 88 countries of the International Whaling Commission (IWC) will tussle this week over controversial changes to a moratorium that has become an icon of green activism since 1986.
Supporters say the system would be more honourable, transparent and practical than today's murky arrangement.
But critics say it would legitimise the slaughter of thousands of the world's most majestic mammals and may tempt former whalers back into the hunt.
What is the 1986 whaling moratorium
On 23 July 1982, members of the IWC voted by the necessary three-quarters majority to implement a pause on commercial whaling.
As the moratorium applies only to commercial whaling, whaling under the scientific-research and aboriginal-subsistence provisions of the ICRW is still allowed.
However, environmental groups dispute the overused claim of research "as a disguise for commercial whaling, which is banned."
Since 1994, Norway, has been whaling commercially and Iceland began hunting commercially in September 2006.
Since 1986, Japan has been whaling under scientific research permits.
The US and several other nations are whaling under aboriginal whaling auspices.
On the other hand, many experts say the moratorium has notched up several successes in saving whale species driven to near-extinction by more than a century and a half of industrial hunting.
Catches have dropped from 70,000 a year in the 1960s, to less than 2000.
The proposed changes to the moratorium aim at coaxing the three nations back into the IWC mainstream.
No longer renegades, the trio would respect a quota that would be subject to outside scrutiny, supported by a DNA-based monitoring system and liable to be ratcheted down.
Under this scheme, Japan, Iceland and Norway would be allowed to kill a total of nearly 12,000 whales by 2020, selected from certain species and specific marine areas.
The annual quota would start at a level about 10 per cent below the whalers' catch for the 2008/2009 season.
After five years, the quota would drop by half for two southern hemisphere species, the minke and fin.
In return, whaling nations would surrender the right to spurn the moratorium by invoking unilateral exemptions, as they do today.
What happens after 2020 would be left to further negotiations.
Iceland and Australia at ends of spectrum
Iceland and Australia mark the extreme ends of the spectrum of opinion on the issue.
Australia's commissioner to the IWC, Donna Petrachenko, argued that as things stand, the deal would undermine the commercial whaling moratorium that has been in place since 1986.
"The moratorium must remain in place," she told the BBC.
"And what we see in this proposal would be sanctioning of commercial whaling in the Southern Ocean, in a whale sanctuary; and commercial whaling in the North Pacific and commercial whaling in the North Atlantic."
Other anti-whaling countries, such as the US, New Zealand and the majority of EU member states, appear willing to sanction a deal provided it meets their "bottom-line" positions.
Tokyo 'wants to strike a deal'
For Japan, that would mean a significant phase-down of their Antarctic hunt, agreement that whale meat is for domestic use only, the end of hunting on threatened species, and the imposition of control measures such as a DNA register of meat.
Whether Japan is prepared to accept a near phase-out of its Antarctic programme is possibly the biggest single factor, BBC reports.
Currently, the draft proposal offers an annual quota of 400 minke whales, going down to 200 after five years.
Conservation groups say these numbers are too high; but Japan says they are too low.
However, some long-time observers believe Tokyo does want to strike a deal and will be offering further concessions as the week unfolds.
Iceland would oppose a trade ban.
"We cannot accept a ban on international trade of whale products," said Iceland's Commissioner Tomas Heidar ahead of the meeting.
"As a principle, Icelanders (...) cannot accept a ban on trade in products from living marine sources that have been sustainably harvested."
Fears other nations may start whaling
Another risk is that some ex-whaling nations, infuriated at what they see as the renegades' success in flouting the ban, may be tempted to dust off their grenade-tipped harpoons.
South Korea has warned it may submit a request to resume whaling, and some analysts think China and Russia could follow suit.
Picture 'not black and white'
Justin Cooke, a committee member from the International Union for the Conservation of Nature (IUCN), described the plan as a "sham."
"It gives the impression that catch limits would be based on [scientific assessments], but in fact they are arbitrary results of negotiation."
However, others back the Australian view that the moratorium must remain intact - not least because some other countries with a whaling past may be looking for a route to renewed hunting.
But those close to the issue say the picture is not black-and-white.
Many nations and most conservation groups have decided that a compromise deal is a lesser evil than the status quo, however distasteful a de-facto lifting of the moratorium might be.
Australia won't budge on whaling in Southern Ocean
One issue that Australia, Britain and Germany have said they will not budge on is legitimating Japan's factory-ship hunting in the planet's only safe haven for whales, the Southern Ocean Whale Sanctuary.
"Right now, the whaling countries hold the key to a 'peace treaty' for whales. We call upon Japan to agree to stop whaling in the Southern Ocean Whale Sanctuary," said Sue Lieberman, director of international policy for the Pew Environment Group.