A close, veteran observer of politics and the global-warming debate e-mails about the current situation at the climate talks:

the walkout of the developing countries is a win win for the alarmists. There was never going to be anything more than a fig leaf agreement.
This walkout allows developed countries to lay the blame on unreasonable demands – while maintain the “we must do something” moral/political high ground.
The developing countries play the victims – hoping for more guilt-induced aid.
Everybody wins and the ball goes into US court on upcoming cap and trade debate/vote.
Getting cap and trade would have been made even more difficult if Copenhagen agreement was lopsided for developing nations – especially any kind of different treatment for China or India, et al.
Obama comes back talking about need for “America to lead the world” – does a head count – then decides how much political capital he wants to spend on getting some kind of deal on cap and trade or alternative.