Devaluation is not an option because of the common currency.

Can Europe s common currency survive? No less a figure than former United States Federal Reserve Chairman Alan Greenspan has now declared that it cannot.

The common currency is now looked at with suspicion.

As a result, Germany bound itself to the idea of ever closer union even more definitively by pledging to join the common European currency, the euro.

Now we have awakened to an existential crisis for the common currency.

The general feeling was that the common currency was doomed.

This is no way to secure the future of the single currency.

Even before it was born, some economists (such as myself) asked whether a single currency would be desirable for such a heterogeneous group of countries.

More realistically, advocates of a single currency reasoned that it would cause people to identify as Europeans, and that the shift to a single European Central Bank would herald a shift of power away from national governments.

A common currency requires unified and centrally agreed monetary and fiscal policies.

The case for capital market integration, and then for a single currency, was similar.

Greece benefited from a common currency, unified capital markets, and free trade with other EU member states.

Margaret Thatcher, from the opposite camp, said in her memoirs I believe the European single currency is bound to fail, economically, politically and indeed socially, although the timing, occasion and consequences are all still unclear.

There have, of course, been many examples in history in which currency unions or single currency states have broken up.

No one doubts that Germany and most other eurozone members would prefer the single currency to continue.

They want to end the common currency, because, in their view, it is undermining the European ideal.

The common currency is the canary in the mine of the global exchange rate system.

In December 2008, the results of a BBC poll of 1000 people suggested that 71 would vote no to the euro, 23 would vote yes to joining the European single currency, while 6 said they were unsure.

First, there is no substitute for timely and coordinated action when the single currency is under pressure.

The convergence of sovereign debt yields implied and required by the establishment of the common currency need not return.

Further, two of the territories under review of the Special Committee share our common Eastern Caribbean currency.

These questions are vital for the future of the common European currency.

In reality, of course, a single currency or fixed exchange rate is not needed for trade to flourish.

Perhaps the same is true of the single currency, which will derive strength and validation from the challenges that it overcomes.

Since the single currency was France s condition for accepting German reunification, Germany played along.

But Germany refuses this option, thus seriously endangering Europe s common currency.

Not only has he kept Britain out of the single European currency over the past four years, he made it clear during the election campaign that he does not expect the UK to join the Euro during the next five years either.

The Nobel laureate Robert Mundell laid out the conditions under which a single currency could work.

As a result, investors and depositors have learned that the erection of financial barriers within the currency area is indeed a genuine risk.

In June, the Euro 2012 football (soccer) championship readily lent itself as an analogy to the turmoil surrounding Europe s single currency.

The final question is what such a eurozone banking union would mean for the single financial market, and especially for EU countries that are outside the single currency.

Indeed, without the single currency, many of these countries would have succumbed to a downward spiral of devaluation, default, and recourse to the IMF.

Perhaps one could interpret the common currency as forcing eventual convergence in policies.

That is what happened in the 1970 s, during the original wave of currency turmoil the Scandinavians and the Swiss negotiated to associate themselves with a European currency regime.

Indeed, in the extreme, some countries could find themselves considering whether to leave the single currency altogether.

Thatcher supported Britain s entry into the European Union in order to benefit from free trade, but she forcefully opposed joining the single currency.

It would be a delusion to imagine that the eurozone need only follow its current path to ensure the single currency s future.

Yet, despite all this, Lukashenko manages to avoid implementing economic projects profitable to Russia (i.e., a single currency).

European believers insist that the single currency is really founded on the strong political will to secure eternal peace in Europe.

The euro s survival in 2012 if only by the skin of its teeth confounded skeptics who forecast Greece s exit from the eurozone and the single currency s collapse by the end of the summer.

All of this raises the obvious question Was the real mistake creating the euro in the first place?

All of this raises the obvious question Was the real mistake creating the euro in the first place? Since I was one of the few Americans to advocate a single European currency, you would be justified in asking Am I having second thoughts?

The Maastricht Treaty established a monetary union, but the political union that is an indispensable precondition for the common currency s success remained a mere promise.

14 European Union, Legislative Acts and Other Instruments, Regulation of the European Parliament and of the Council laying down the framework for the creation of the Single European Sky.

The introduction of a common European currency was successful political integration by means of a constitutional treaty a failure.