Climate: A defining issue
A couple of weeks ago, the cat came well and truly out of the bag: there would not be a legally binding treaty at the UN climate summit in Copenhagen next month.
Or will there?
During his meeting on Tuesday with China's President Hu Jintao, President Obama appeared to indicate that some sort of comprehensive agreement was still possible.
Then, Danish Prime Minister Lars Loekke Rasmussen, speaking to a pre-summit meeting of environment ministers, called for developed nations to bring firm targets to Copenhagen - targets that should be binding.
All of this is very much at odds with statements from a number of European officials and ministers during and directly after the recent UN negotiating session in Barcelona, which were variations on the theme that a legally-binding deal was "unlikely", "extremely unlikely" or "impossible".
It certainly poses more questions. What does "legally binding" mean in this context? What does the alternative being bandied around - "politically binding" - mean?
And where does the formulation that President Obama used in his Beijing speech - "not a partial accord or a political declaration, but rather an accord that covers all of the issues in the negotiations and one that has immediate operational effect" - fit in to the overall picture?
We are into a miasma of nuance here; but for different parties, all of the nuances are important, so it's worth having a look at what's being suggested, what might actually transpire, and who's likely to be happy or unhappy.
So let's go back to the Bali meeting nearly two years ago and the pledge, in the Bali Action Plan (BAP), to produce something new by Copenhagen.
The BAP doesn't actually prescribe a legally-binding treaty, although that's an interpretation and an outcome that's been accepted by most governments as desirable and necessary.
You could argue that something legally-binding is implied by the agreement that all developed countries must adopt "measurable, reportable and verifiable nationally appropriate mitigation commitments or actions, including quantified emission limitation and reduction objectives".
What is explicit is that a Copenhagen agreement must "achieve the ultimate objective of the [UN climate] convention" - in other words, must stabilise "greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system".
In the broadest sense, then, there is acknowledgement by all governments that everything enacted before - the UN climate convention of 1992, the Kyoto Protocol of 1997 - could not achieve that goal, and something new was needed.
That "something else", according to BAP, would have to be bigger and bolder, encompassing emissions cuts by rich countries, curbs on the rate of growth of emissions by major developing countries, and finance and technology transfer to help poorer countries constrain their emissions and adapt to climate impacts.
It was described by UK Foreign Secretary David Miliband as the most complex set of international negotiations ever, on any issue.
Two principal factors now line up to prevent a full binding treaty emerging in Copenhagen. One is the sheer amount of negotiating needed in a tight period of time; the other is that the US has yet to put any commitments on the table and may not do so before the summit.
What a number of developing countries are still demanding - joined, apparently, by Mr Rasmussen - is something that is firmly binding even though it might not carry any formally legal weight, let alone the paraphernalia of a full treaty.
But how can that be?
Recall first that these treaties don't become binding on anyone until they've been ratified by enough countries to gain the status of international law. In the case of Kyoto, that took eight years - and in the case of Copenhagen, we don't yet have an agreement on the legal form of any treaty, let alone what would trigger its adoption as law.
Secondly, one of the bases for the Copenhagen process has been that "nothing is agreed until everything is agreed".
(A better phrase might be "nothing is binding until everything is binding, because certain things such as an agreement on Reducing Emissions from Deforestation and forest Degradation (REDD) could conceivably emerge as a self-standing entity whatever the carnage around it.")
Are governments really going to grant binding status to something that includes main numbers on emissions targets and finance, but omits details that for some nations might turn out to be crucial? This has to be a consensus of 192 countries, not a majority vote.
Thirdly, what is there except international law that can bind countries to anything?
When it comes to the form and status of something that is not international law but is more than just a promise, I for one am out of ideas; if anyone has a clearer notion, I'd be very happy if you can spell it out for us in a comment.
A fourth issue is that some countries are very unhappy about signing up to anything that is not legally binding. A number of developing nations including Sudan (chair of the G77/China bloc), Grenada and Barbados have been making noises about not agreeing to anything that is not legally binding.
Their position is that we had the politically-binding agreement in Bali. In a sense, we had it in Rio; this is supposed to be the time for delivery on those fine words.
And it not just small developing countries; a number of European delegates have said that no deal is better than a bad deal, and presumably if they do not see the requisite amount of "binding" in the text, they will not sign, whatever embarrassment that might cause the Danish hosts.
The runes on this story appear to shift their shape daily. Experienced negotiators and observers suggest the fog is unlikely to clear before the final Copenhagen dawn on December 18th.
To the outside observer, it might seem a strange old way to try and solve a problem that most governments acknowledge as a serious and urgent threat to humanity's prospects.
But if there's one thing that governments appear to consider truly binding in this process, it's the requirement to obfuscate and procrastinate right down to the wire.