In the circumstances, the position that Labour is gradually carving out for itself on economic and monetary union is the most sensible available stance. In fact, it is the only tenable one; Kenneth Clarke must be wishing he could persuade the Conservative Party to endorse it too.
If monetary union is working well, and if the British economy is suffering by remaining outside a single currency bloc, then the chances are a Labour government will sign up to the euro. The Labour Party's door, in other words, is hesitantly half-open to the single currency.
The Conservatives' door is half-shut, and swinging firmly closed. We can understand the Euro-sceptics' anxiety. We would be happier if all this were not really happening. The democratic threat posed by a single currency, on top of the economic uncertainty about its effectiveness, both lead us to feel profoundly wary.
But no one is going to wish this thing away. That essentially, is what the Conservative campaign team want to do. Their weeping lion (the latest Saatchi image) suggests a somewhat fairy-tale view of the future. The evil-eyed wicked witch of the west, otherwise known as Tony Blair, is forcing a single currency on his hard-pressed munchkins. But the tearful lion accompanied by a brainless scarecrow and a heartless tinman are going to bound off down the yellow-brick-road and home to safety, far away from those nasty Europhile lefties.
Nonsense. There isn't anywhere for Britain to escape to. Monetary union is happening. It will almost certainly happen on schedule, since the French and German political elites are so committed to it.
If it works, and that is still a big if, then it is hardly plausible that Britain could stay out for ever. Imagine Europe in 2010. Inside a large single currency bloc are Germany, France, the Benelux countries, Austria, Italy, Spain, Scandinavia, the Czech republic, Hungary... the list goes on. Within the huge euro-zone, businesses don't have to bother their heads about currency speculation. They don't have to worry that the cash they pay their producers with will suddenly rise in value compared to the cash they collect from their customers across the border, squeezing their profit margins beyond their control. Across the Channel, however, things look rather different. Companies have to add to the hassle and cost of sending goods across the sea to European customers, the unpredictability of currency changes and the higher interest rates that Britain would probably suffer. It does not take a Toyota chief to work out the best place for future investment. And the British people, watching the disparities grow, are likely to opt for a single currency too.
So Robin Cook is right to say that if EMU is successful, a Labour government would find it hard to keep Britain out. But he is equally right to prevaricate about going in as part of the first wave.
Consider the timetable. Joining up would require some quick thinking, quick decision-making, and quick persuading, by a fresh and untested Labour government. Parliamentary timetables would be entirely clogged up by Euro legislation. A new Blair government would have to risk going to the polls in a referendum on a single currency, after hardly any time to make a positive case for joining. Although the British public may accept the euro if they can see it working, they are too conservative and too sceptical for a leap in the dark.
Moreover, serious problems with the euro remain. The risk of economic crisis in Europe under a single currency remains considerable. The low interest rates currently needed by Germany would be hopelessly inflationary if applied to Britain, which came out of recession earlier than the Continent. If structured badly, the single currency could lead to terrible persistent unemployment in some parts of the union, provoking political tensions that could destroy the entire project. Waiting to allow further economic convergence - and that means real integration of European markets, not just similar inflation rates and government borrowing requirements - has a lot to be said for it.
And then, of course, there is the democratic deficit. Signing up blind to an economic system which provides almost no democratic accountability for policy decisions which have a huge impact on people's lives would be a mistake. A British government which is not opposed to a single currency in principle should be fighting fiercely to influence and reform the EMU project before taking the plunge. So Mr Cook's position makes sense: accept the difficulties of staying out for good, point out the reasons for staying out in the short term, and keep all options open along the way.
The best aspect of his position, however, is that if a Labour government is elected, we will have a proper discussion about the merits of the single currency. With the Conservatives in power we cannot have that argument, because any plausible Tory leader would have to suppress the full range of views within his or her own party. Out of power, Tories would be free to give full voice to their views, pro-, anti-, and not entirely sure.
Robin Cook, Gordon Brown and Tony Blair, and everyone else, would have plenty of time to listen to Mr Portillo and Mr Clarke arguing, while finding out (because they might start talking to us) what the French and Germans are really up to.