We all want to see the plan

Jurgen Habermas says:

Without the dynamic of economic interests, the political union would have probably never got off the ground. This dynamic only strengthens the worldwide tendency toward market deregulation. But the xenophobic perception of the Right that the socially undesirable consequences of this lifting of boundaries could be avoided by returning to the protectionist forces of the nation state is not only dubious for normative reasons, it is also outright unrealistic. The Left must not let itself be infected by such regressive reflexes.
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What is vaunted today as the "European social model" can only be defended if European political strength grows alongside the markets. It is solely on the European level that a part of the political regulatory power that is bound to be lost on the national level can be won back. Today the EU member states are strengthening their cooperation in the areas of justice, criminal law and immigration. An active Left taking an enlightened stance toward European politics could have also pressed long ago for greater harmonisation in the areas of taxation and economic policy. The European constitution now creates at least the conditions for this.

Daniel Cohn-Bendit says:

A French 'no' will be the beginning of a period of confusion, or recrimination, of gradual unwinding of what we have already achieved in Europe. I fear that, for once, the right-wing press in Britain is right. A French "no" would be the prelude to an attempt to impose a purely economic vision of Europe, a market vision. Murdoch would jump for joy.

Denis MacShane says:

Europe’s new constitutional treaty belongs neither to the left nor the right any more than the French or American constitutions, in themselves, define the political or social choices of France and the United States. It is up to the left in Europe to develop a new agenda to achieve full employment and social protection. Let the conservatives, isolationists, souverainistes, and populists say No. The new constitutional treaty contains language for 450 million citizens which workers elsewhere on the planet can only dream of. The left should say Yes to Europe.

Pierre de Lauzun says:

At heart, they know that Europe can only be built on the basis of nation states. It's for that reason that what they call the Constitution is actually an international treaty. But they do not draw the right conclusion from this: the myth of substituting Europe for nation states is utopian. Europe is above all the pooling of tools, whose true - national - political authorities judged that they were better implemented together than separately. If they want to go further than this, they need to define positively what the people of Europe objectively have in common, and to cease trying to build Europe in the abstract.

But they prefer to continue with the political myth. Lacking content, the adopted solution has become procedural: taking abstract principles and judging any decisions based on their variation from them. The procedural and legal approach entirely invades the language of debate. We should not therefore be surprised by the indifference and sometimes hostility of the people, in spite of their previous benevolence. Europe is the paradox of an undemocratic construction built on a democratic foundation. It remains more the fruit of the will of the elites than of the people. Each stage was decided from above and was ratified, as well as it could be, after the fact. Being democratic is not its aim, in spite of the European Parliament: there is no public discussion between two parties or two programmes, sanctioned by the ballot boxes, in a common political space.
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For the first time, the referendum puts the question of the nature of the European project. It's no surprise that this should happen in France, where a voluntaristic faith in integration is combined with a refusal to recognise the inadequacy of the political basis of Europe. ... Without the referendum, which let democratic light in on the Brussels game, nobody at the level of the French voters would have heard the constitution talked about - and it would have passed in the end, in one form or another. But this surreptitious approach can't be continued indefinitely, certainly not in the field of politics. We need to get back to reality - and the merit of the current debate is that it enables us to do so.

Zoé Magariños-Rey says:

the main argument for a Yes vote consists in saying that the Constitution consecrates a community of values, with particular reference to democracy. It is all the more astonishing that nothing in the Constitution brings the EU closer to its citizens. ... The powers of the European Parliament have been augmented quantitatively but not qualitatively. The most anti-democratic features of the EU remain: there is no separation of powers; there is nothing resembling a principle of popular sovereignty; the executive is politically unaccountable, with the exception of errors of management ... This Constitution has been put together behind our backs, by delegates who may well be representative but were co-opted - in just the same way that Europe has been built by mechanisms whose inexorability leaves us sidelined.

It is very tempting to treat this referendum, not as a matter of domestic politics, but as a historic referendum on the construction of Europe. This would be to overlook the 10% of new provisions, buried within the Constitution, which are the real subject of the referendum, given that the other 90% of the text will remain in force whichever way the vote goes. A fog of political and media propaganda, broken all too rarely by attempts at explaining the issues, has ended up promoting the impression that we're being taken for idiots: yes, the French people will be consulted, but they must not be allowed any alternative to accepting everything.

Paul Anderson says:

Although I agree with rather a lot in the Green manifesto, including the proposals for a citizen’s income and for a massive rethink of environmental taxation, I can’t swallow the idiotic Euroscepticism. Campaigning against the European constitution as nominal pro-Europeans because you want a better one? Get serious.

and:

What I really can’t get my head around ... is the sheer idiocy of left-wingers deciding to become a tiny, swamped minority in a campaign that will be (a) overwhelmingly dominated by the Tories and far-right loons who want to destroy the welfare state, reduce workers’ rights, send immigrants home and tell the frogs to hop off; and (b), if successful, a massive boost for the Tories’ next election campaign. What on earth is going through the left Europhobes’ minds?

Meaders says:

This should not be difficult. It is a free market treaty with a few sops. That's why the No campaign in France has been led by the Left.
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Nowhere in this is any sense that other agencies or forces may exist that are better placed to deliver social justice than the venal political classes of Europe, committed for decades to a broadly neoliberal vision of the world. Quite why a declaration of faith in the existence of the EU by its citizens would alter their course is unclear.

(Brief excerpt from an excellent post.)

Sarah, in comments at Meaders' blog, says:

Surely the important thing is not how a vote against the Constitution would be perceived but the fact that the Constitution should not be adopted in the first place. Because if it is adopted, "undistorted competition" will become legally enforceable (as set out in the third part of the Constitution), and this also applies to what are quaintly called "services of general economic interest" (known to normal people as public services). It is specified in the Constitution that it is a duty of member states to introduce further liberalisation (as quickly as their circumstances permit). It is further specified that they have to increase their military spending (nothing optional about that). This is not really a Constitution; it is a straitjacket for every member state's future domestic policy.

Lastly, Henry Farrell says:

the EU is a political project dressed up in technocratic clothing – it’s succeeded in part because its day-to-day activities sounds so boring to outsiders.

The problem with this, of course, is that over time, the European Union has begun to leach legitimacy, as it has become ever more powerful and less accountable. Hence the long-lasting debate over the European Union’s “democratic deficit” and how best to solve it. The primary solution over the last fifteen years or so has been to give more power to the European Parliament, which on its surface is the most ‘democratic’ of the EU’s institutions. The problem has been that European voters don’t pay very much more attention to the Parliament than they did when it was a toothless congeries of windbags, so that the Parliament is accumulating power without much in the way of democratic responsibility ... Thus, we have a set of institutions (the European Union) which are increasingly politically powerful, but which don’t have much democratic legitimacy.
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While EU policy is shrouded in technocratic gobbledygook, it has very substantial political consequences. Nor are these consequences what you might expect. The European Union is typically perceived by English-speaking non-experts as a vaguely social-democratic bureaucratic leviathan, in part because of criticisms from the British government and the British tabloid press over the last couple of decades. In fact, its most important impact has been to further neo-liberalism by creating European markets, and by wearing down the particularities of national economic systems that are incompatible with these markets. The European Union has taken over vast swathes of economic decision-making, and effectively taken them out of democratic control. It’s no wonder that people on both the left and right are beginning to get upset by this; what’s more difficult to explain is why it’s taken them so long to begin to mobilize their frustration.

All this means that the traditional means of furthering European integration – agreeing new treaties among heads of government, and then getting them ratified by a supine public (when the public is consulted at all) won’t work any more. Nor will tearful appeals to that public to pass the Treaty on the nod, because of the inherent worth of Europe, gloire nationale or whatever-you’re-having-yourself work very well either. For better or worse, the European Union is becoming increasingly politicized. Nor is this likely to change in the future. But exactly because it’s becoming politicized, it’s starting to become politically present in a way that it hasn’t been in the past. As best as I can tell, the question is beginning to change from one of whether Europe, in some abstract and ineffable sense, is ‘good,’ to one of what kind of Europe is good (as usual, the UK is the glaring exception to this generalization). .. the recent decision by the European Parliament to remove Britain’s opt-out from the Working Time Directive was portrayed by both sides as a blow in the fight over whether Europe should adopt a liberal-reformist or more traditional social-democratic model.

Thus, a new debate is beginning to emerge over what kind of European Union we should have – a Europe that’s more aligned with the social-democratic model, or a Europe that’s closer to the classical liberal approach; protection versus free markets.
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these arguments are less obstacles to European integration than the birth pangs of a European Union in which voters actually begin to pay attention to what’s happening at the European level. The European Union is becoming a political space, in a way that it hasn’t been in the past.

Not much to add to all the above (you'll be pleased to hear), except: interesting times. Let's see the plan. I don't believe that the Left opposition is going to make the running - but let's not fool ourselves that it will have no influence at all. (Pessimism is not realism.)

Above all, let's keep the discussion going rather than shutting it down. The last thing we need is another round of nosepegs.