Last week there was a string of voices against the slow divorce: from the US, Germany and smaller Member States including Ireland, to business leaders and former Conservative ministers (see Jon's round-up here). What makes the speech such car-crash politics is that it's basically aimless posturing. There's nothing Cameron can promise that the rest of the Member States are prepared to give that would be satisfactory to the hardline Eurosceptics, and there's not really much that you can practically put your finger on for repatriation that would not politically undermine the single market (taking away more social and environmental responsibility from the single market would mark the UK out as a free-rider encouraging a race to the bottom within the EU - something politically unacceptable to even the UK's economically liberal allies).
Even if areas where identified, the emotionally charged announcement of plans without background work being done on negotiations is a ridiculous strategy. It seems that the UK strategy is based on the German fear of a Brexit along with the support of some traditional allies, but as the Charlemagne blog on The Economist says:
"The reality is that, if forced to choose between Germany and Britain, Mr Rutte (and almost all of Britain's northern liberal allies) will take Germany's side—as he did over Mr Cameron's pyrrhic veto of the fiscal compact in December 2011 (see my piece from the time).
But such tactical gestures [by Germany to accommodate British Euroscepticism] are very different from the notion that Germany, or anybody else, would be willing to create whole new carve-outs for the British from EU rules beyond its existing exemptions (from the euro, the Schengen free-travel area and perhaps parts of justice and police co-operation)."
The inability to work with the other Member States that do have common economic concerns for repatriation demonstrates he diplomatic ineptness of Cameron's government. It also indicates a failure to consider the reaction of other Member States to the renegotiation - what if Britain's terms were rejected in an Irish/Dutch/French referendum? A belligerent posture doesn't help win treaty change. Pinning it to other EU changes could lead to it being a casualty of a rejection for unrelated reasons as well, so even careful diplomacy could fail to deliver the goods.
The best Cameron can hope for is a short reprieve from Eurosceptic pressure. Without agreement for the opening of negotiations, Cameron would be forced to play a more belligerent hand when Eurozone legislation comes through, placing him in the difficult spot of blocking reforms he has encouraged or called for in some way for unclear goals or to attempt to resist Eurosceptic pressure to obstruct Eurozone reform.
Cameron will need some good airbags...