Centrist politicians are hard-wired to look for a middle way when confronted with difficult problems. So after absorbing the shock of Britain's vote to leave the EU last June, it is only natural that so many have sought one on this most perplexing issue. It goes by the name of "soft Brexit", to contrast with "hard Brexit", which refers to an uncompromising break. But is such a solution viable?
This question revolves around one issue above all: membership of Europe's Single Market. The Single Market allows for the free movement of goods, and some services, across Europe's borders. This came into being in 1990 as intra-European trade was stagnating, and restored momentum. The problem was that Europe's free trading arrangements at that time did not go far enough. There were no tariffs, but plenty of scope for non-tariff barriers. There were many such barriers - I remember a particular story about all French imports of one particular type having to be sent to Poitiers to be inspected.
The Europeans had a clear model in front of them: the United States of America. This towering economic power was so successful in large part because of its huge domestic market, which gave businesses time to develop products before having to tackle export markets. But here we bump into a famous trilemma, first articulated by US economist Dani Rodrick in his book The Globalization Paradox. People must choose between democracy, national self-determination and the benefits of global integration. You can have two of these, but not three. To achieve global integration means setting global rules. If nation states choose to participate in globalisation, they will sacrifice their voters' rights to change the rules. The only way to make it democratic is to make it so at the global level, which means losing national autonomy.
And so forming the Single Market meant that the members of the European Union sacrificed significant sovereignty - albeit with the creation of some democratic structures at European level: the European Council of heads of state, and the directly elected European Parliament. Critics of the EU say that it is undemocratic - but the only ways to address this are either to dissolve it and lose the Single Market, or strengthen its union-level democratic structures, undermining the nation-state further. The problem with soft Brexit is that it attempts have all three elements of the trilemma at once.
Brexit means British withdrawal from the European Council and Parliament, to say nothing of its influence in the European Commission, the EU's executive arm. But taking part in the Single Market, or even aspects of it, means leaving the rule-making to these European institutions. This cannot be acceptable. Norway, and to some extent Switzerland, suffer this indignity already. It is hard to see it working for such a big country as Britain. Voters would rightly ask what the point was in leaving the EU. "EU rules" would still be the bureaucrats' excuse of choice for badly implemented regulation, alongside that British favourite "health and safety". Political suicide, surely?
Neither will it be easy to pick apart the structure of EU regulations so that the country opts out of bits of it. British politicians often assume that there is a deal to be done to limit EU migration into the UK. Businesses want to tackle EU labour regulation and various other things, like regulation of poisonous chemicals. The trouble is that the other EU countries will see this as trying to get an unfair competitive advantage - which could undermine the entire edifice.
And furthermore, Britain's bargaining position is weak. One of the key arguments made by the Brexiteers was that because Britain imports so much from the rest of the EU, the EU (German car makers, and French cheese makers in particular) will be desperate to give us an advantageous deal. That looks optimistic. Take the motor industry. This has significant economies of scale, and a single national market, even the size of Britain or Germany, is not enough to sustain a domestic industry. Before the Single Market, Britain's motor industry was dying. After it Japanese and other carmakers invested in factories in Britain as an export base for the whole of Europe. Britain's car industry revived, though it is still in deficit. If Britain withdraws from the Single Market, this industry comes under threat. If it withers, then surely other EU countries will gain. Why should Volkswagen press for an easy trade deal that would save their Japanese competitors? Britain can't sustain its own motor industry, so it will have no alternative but to keep importing cars from its nearest neighbours in the EU - and perhaps in even greater quantities as Nissan and others are forced to divest.
I am tempted to suggest that angling for soft Brexit is just the bargaining phase of the five stages of grief from Remain supporters, coming after denial and anger. Depression comes next.
Of course the real situation is not as black and white as I am painting it. But if Britain has to be outside the EU, its best bet is to start with hard Brexit, and then negotiate arrangements sector by sector - much as Switzerland does. Except that we would not go anything like as far as Switzerland. But we have to acknowledge that the UK will lose its comparative advantage in industries that benefit from the Single Market - like the motor industry. That will mean quite a bit of dislocation.
But it won't be the end of the world. Basic economics teaches us that where comparative advantage diminishes in one sector, it emerges somewhere else. The country may be poorer as a result, but it need not be a disaster. Where will this new comparative advantage lie? We cannot do a Singapore, a favourite of some Brexiteers - which exploits its strategic position on key Asian trading routes. But industries that are not subject to Single Market rules will be at a relative advantage. This may help Britain's successful service industries - though making headway in this highly protected arena will be hard. The county's geographical position should help wind and tidal energy - though not solar energy, presumably. We also need to look for areas where EU regulations look badly implemented.
But just how big any short-term disruption will be is unclear. It is also not clear that the British public actually intended to sign up to it. If they didn't the only way back is to reverse the Brexit decision itself. That is the true alternative to hard Brexit. But that is another matter.