But why would a default by Greece cause trouble for the Euro? Is there an explanation understandable to a non-economist like me?
Sure people will suffer, will possibly lose their savings. There will be riots in Greece causing death and destruction. Some Greek voters may even die of hunger (and it's the voters who are responsible for the irresponsible fiscal policy!).
But why would a default damage the Euro as a currency? When Argentina went bankrupt in the 1990s (with the currency pegged to the US dollar), there was no damage to the dollar - in fact it had a much higher value than today!
The problem in itself is not Greece but the banks that have given money to Greece and if Greece default, so will the banks most likely.
Argentina was one country. EU is not one country but bunch of countrys that some of them are econimically viable and then there are countries like Greece, Portugal and maybe Spain that are not economically viable. EURO has that problem that when you are trying to have one policy and interest rates etc, it effects different economical areas differently and will cause problems elsewhere if it corrects something here.
Greece could "easily" correct it's economy by just jumping off the EURO-wagon and have their own currency and having their own economical policy just like Argentina did. But as they will not do this they don't have any possibilities to effect their own affairs as most of the things that are essential tools for economical policy because all of these things are controlled by the EU and EURO. Greece should not be part of Euro nor should Portugal and some other countries.
Euro was a nice concept and a dream and now it's evident that it doesn't work and it causes problems to so many country that it's just ridigilous to have the system anymore. Countries that have the same currency should be almost in the identical economical situation for the system to work.