Niall Ferguson tror ikke euroen ryker, men han tror at de ti landene som står utenfor eurosonen vil måtte betale en stadig høyere pris i både penger og uavhengighet, og det kan tvinge frem en revurdering av om EU-medlemskap i det hele tatt er tjenlig.

Britene ville trolig stemt for å forlate EU, hvis de fikk sjansen, tror Ferguson.

Denne utviklingen var forutsigbar da euroen ble innført med Tyskland som primus motor. Tyskland ville komme ut på toppen, og landene rundt Middelhavet ville havne i avhengighet og gjeld. Resultatet vil bli høyere skatter nord og større arbeidsledighet i sør, spår Ferguson. Det er prisen for at eurosonen overlever.

But the fate of the European Union itself will be very different. The creation of the single currency — obeying the law of unintended consequences — set in motion a powerful process of European disintegration. The fact that not all 27 E.U. members joined the monetary union was its first manifestation. Today we have a two-tier system, with 17 member-states sharing the euro, but 10 other states — notably Britain — retaining their own currencies.

The result is that key decisions today — particularly those about the scale of transfers from core nations to the periphery — are being made by the 17, not the 27. But the 10 non-euro members may still find themselves on the hook to help fund whatever combination of bailout, haircut and bank recapitalization the 17 decide on. They may also face more stringent financial regulation or a financial transaction tax, ideas that are much more popular in Berlin than in London.

This is an unsustainable imbalance. If the euro countries are intent on going down the road to federalism — and they don’t have a better alternative — the non-euro countries will face a stark choice: giving up monetary sovereignty or accepting the role of second-class citizens within the E.U.

Under these circumstances, the logic of continued British membership in the E.U. looks less and less persuasive. British public opinion has long been deeply Euro-skeptic. If it came to a referendum, as many Conservatives would like, Britons might well vote to leave the E.U. And under Article 50 of the Treaty of European Union, withdrawal would simply need to be approved by a qualified majority of E.U. members.

In the great game of European Jenga, most people expect the French government of Nicolas Sarkozy will fall next year. But the thing that could cause the European Union to topple, or at least shrink in size, would be the outright withdrawal of Britain. And that has started to look quite possible.

Niall Ferguson, a professor of history at Harvard University, is most recently the author of “Civilization: The West and the Rest.”

Why E.U. collapse is more likely than the fall of the euro