Tabloid excitability aside, The Sun is right to have noticed that the Labour leadership's cautiously favourable approach to EMU has been surreptitiously replaced by a tone of relentless optimism. It is also right to make a fuss about it.
The signs are that policy has changed from waiting till EMU was up and running before assessing whether Britain should take part. Such was the promise of Gordon Brown's statement to the House on the matter last year.
Now, however, we have the purposeful language of advocacy, intended to prepare the public for early entry. Last week Mr Blair hinted strongly in Strasbourg that he favoured unconditional entry: "We can remain independent of the euro. The question is whether it is in our best interest to do so... The euro will generate stability... I am optimistic." This sounded suspiciously like the starting bell for a concerted campaign to erode public reservations.
But how can the Prime Minister possibly know whether the euro will generate stability? It may well have the opposite effect, particularly given the as yet unknown impact of the Asian crisis on European economies. EMU is a strongly deflationary project, requiring adherence to a single, invariable interest rate to succeed. This combination is not what most sober calculators would call grounds for optimism.
Out of the 20 Sun tests of the "Perils of the Single Currency", all but three - the ones invoking mawkish nationalism and exaggerated accounts of France and Germany's economic weakness - were reasonable criticisms of the project and its suitability for Britain.
From interest rate inflexibility to convergence differences between Britain and Europe, the dislocation between the low-tax strategy adopted by Labour to the far higher averages in continental Europe; from the democratic deficit of unelected bank chiefs running national economies to governments left without the options for change if voters protest - all these arguments should be ruthlessly tested before Britain commits itself to EMU.
The Tories' extended blood-letting over Europe has persuaded new Labour to jam the lid on debate. Those on the centre-left who fear that European leaders took a wrong turn at Maastricht can easily be branded as fearfully clinging to the paraphernalia of island pride.
It is not like that at all. The "European ideal" which Mr Blair quite rightly believes to be a force for good on a continent that has sacrificed so much to war is ill-served by the precarious project of EMU. The really worthwhile historical mission - enlargement of the Union and the reform of its institutions, has been delayed by the concentration on the creation of a currency elite.
EMU-philes have been fortunate in their enemies. Euroscepticism allowed itself to be defined by left-wing warhorses such as Tony Benn and the small-minded, flag-waving xenophobes of the Conservative Right. In the latter category I included some clever but miscalculating politicians such as John Redwood who are too cultivated to be anti-foreigner themselves, use the imagery of parochial nationalism to make their arguments more accessible.
That is why I never describe myself as a Eurosceptic. I once went to a meeting of the Anti-Maastricht Alliance and found myself in a room full of Sid and Doris Bonkers. The term "Eurosceptic" has now lost its root meaning of "those distrustful of a single currency/integrationist project" and become a neologism for Conservative hyper-patriots or old Labour high spenders.
But centre-left EMU-Sceptics - or Euro-thoughtfuls - are a different breed. I believe there are quite a lot of us out there - and not a few in new Labour who are not so much convinced EMU-supporters as scared to be seen to be unconvinced by anything the leadership proposes.
Euro-thoughtfuls are not theological, unconditional Eurosceptics. We do not warm to the strident cry of "Save the pound" under which the alliance against the euro is currently running. It is too reminiscent of the sort of thing people say when they are shaking their walking-stick at you. It is not the pound as a totemic object of Britishness that we are arguing about here. It is the single currency.
If, well into the next century, the project turns out to have been a runaway success and Europe is blooming in freedom, prosperity and goodwill, full of satisfied and employed electorates, I shall eat my worries and say I was wrong. Until then, I reserve the right to doubt.
It is the centre-left's duty to be sceptical about everything - to look beyond the blinkered certainties of ideology. But monetary union is an ideological project. It was intended by the French to create a supranational political entity to constrain Germany. Britain will certainly have less influence outside: but it will have greater freedom of manoeuvre - perhaps a more useful trait in a highly competitive world.
EMU's dirty little secret is that a lot of things will have to happen afterwards which its proponents hide from us today. Without harmonisation of tax, pensions and eventually welfare provision, it cannot be sustained. We have not yet had an open debate about the consequences of such a major shift in the way we are governed and the consequences for the accountability of those we vote into power.
Mr Blair says that he does want a Europe which is inward-looking, protectionist and mired in bureaucracy. I believe him. But what does he see in the present EU that leads him to conclude that the Union is prepared to reform itself?
The language of inevitability and momentum is misleading. There is always a way back. Mr Blair is a flexible and responsive politician. He has often reconsidered earlier positions and been applauded for so doing. He should apply the same stringency to his European policy and hold Britain from taking a part in the experimental theatre of EMU until such a time as there is sound evidence that the most potent fears were unfounded.
He should do so not because The Sun says so, but because it is the act of a truly outstanding statesman to resist the follies of his contemporaries.