Are sovereignty referenda a good idea in a borderless Europe?

The Scottish will have a referendum in 2014 to decide whether they want to become an independent country. The British will have a referendum soon after to decide whether they want to stay in the European Union. In Catalonia, there is a movement to call a referendum to decide on independence, if possible in 2014. In these three cases, the starting pressure for the referenda comes from populist nationalist politicians. In some cases, mainstream politicians are unable to resist the pressure and accept calling a referendum as a way to reduce political pressure. However, these referenda may be very divisive, and do not leave room for a civilized debate that tries to build bridges across communities and across people with different views. The public opinions of the affected countries may spend all their political capital and resources to fight these issues whereas the economic crisis and the sharing of its costs are buried under nationalist songs and flags. Some of us think that in Europe the crisis can only have a European federal solution, and we wonder what would happen to Europe if the fashion to hold populist sovereignty referenda in an interconnected world with shared sovereignty generalizes to more territories. Europe is a land of multiple nations that overlap across state borders. Only a borderless Europe will make possible the coexistence of identities, languages and ethnicities that populate our continent.