We urgently need a post-mortem inquiry into what on earth went wrong in Brussels this past weekend. At the very least a departmental select committee needs to ask some very searching questions.
Contrary to the whoops and cheers of the eurosceptics, British business and sensible commentators are waking up to the reality that Britain is now more isolated in Europe than at any time in the last forty years and at risk of being excluded from the heart of European decision-making at an absolutely critical time. Far from guaranteeing safeguards for the City and the British financial services sector, we have been left in a position where a new fiscal stability club of 26 might start to develop institutions and make rules which pan out very badly for British business and British jobs.
Sarkozy has been accused of intransigence and of manoeuvring against the interests of the City of London. Perhaps that is part of a French president's job description. The real surprise is why every other EU nation - even those who are not in the Eurozone and including famously eurosceptic Denmark - sided with Sarko and not with our Prime Minister.
It's not as if the demands we were making were that unreasonable:
Protections for national financial regulation that would actually have enabled tougher rules like the Vickers proposals to be implemented without challenge; higher capitalisation targets for banks which would have made all European banking safer. There were none of the loopier eurosceptic demands for repatriation of powers or rewriting of social legislation in the middle of a crisis. So why did even this modest negotiating position fail?
One explanation, albeit unlikely, is that Mr Cameron was a poor negotiator on the night or that British diplomatic effort was inadequate. At the very least he may now regret the throwaway leadership election pledge to leave the main centre-right political grouping, the European People's Party. This excluded him from a crucial pre-summit pow-wow of right wing European leaders in Marseilles, where he might have wooed many natural sympathisers.
Perhaps European leaders were genuinely exasperated with Britain's single-minded defence of the City of London, so happy to profit from dealing in euros but apparently unwilling to lift much of a finger to help save the currency from collapse.
Or is the explanation simpler than that? That the endless torrent of xenophobic eurosceptic rhetoric had so alienated other European leaders that when push came to shove we didn't have a friend in the room. When some Tory MPs compared David Cameron's position in Brussels to that of Neville Chamberlain at Munich in the days before the summit, you can imagine any last ounce of sympathy for the British position evaporating completely.
Liberal Democrats won't throw our toys out of the coalition pram over this. There is too much at stake: from the continuing need for a stable government to clear up the mess left to us by the last government, to delivering on promises like the income tax break for the lower paid, or the pupil premium or the greening of the economy.
We are not about to put all that at stake.
But Liberal Democrat ministers will now have to work much harder with Conservative colleagues to rebuild trust and relationships within Europe. As the new treaty process develops, we need to make sure that Britain's influence over events is not lost altogether. Lib Dem negotiating skills, contacts and positive commitment will be crucial to that process.
But we have a right to ask how exactly we got into this situation and demand some explanations.