koanarc....very interesting questions. Due to the clearly increasing interest in this topic, I am going to write a series of blog posts on the crisis (according to what I know - not claiming to be a fortune teller or a sage of any kind, but it seems people are interested).
Well, I wouldn't say the Euro is near collapse just yet. The Obama Administration would never let that happen...i.e. assuming that the Eurozone bigwigs (i.e. Germany, France, etc.) want it to collapse - which I don't see why they would - a collapse of that nature right now would threaten the overall economic recovery. So the powers that be, are doing (and will do) everything in their power to prevent that from happening.
In terms of the impact over the long term, i.e. coming decade, I would say that provided that the Euro can get through this it should prove good for the EU. Because the only way they are going to get through it, is if the EU + IMF bailout the problem states. We have already seen the major sacrifices that have been demanded of Greece as a condition for getting the bailout - http://news.bbc.co.uk/1/hi/8656649.stm
Although Greeks might be pissed at the 'financiers' for imposing 'harsh' conditions to the bailout, in the long term it will be healthy for Greece. They have to go through a bitter, deep, cleansing period (kind of like the bankruptcy proceeding that GM had to go through to get out of their onerous contracts they had with labor unions & dealer network) to get to a more healthy fiscal position. Unless I am mistaking the resilience of the politicians to weather the storm, I strongly suspect that they will persevere through the political maelstrom and do what needs to be done. Then in 5 - 10 years, we could see some strong growth coming from Greece again - however it all depends on what policies (aside from the austerity measures) they implement.
By bailing out Greece and demanding significant austerity measures, they are attempting to contain it locally. The issue is that if they don't take their pound of flesh, the other states/countries will expect the same. So to nip the moral hazard element of it, they (the EU & the IMF) have to be harsh. It's for everybody's own good.
In terms of the strong legal basis...I will cover this in my blog post. I believe there is some legal basis for it - but I am drawing a blank right now. I am going to do some research and include it in my post. Stay tuned, will post on HN once I am done. At the very least, even if there isn't an explicit legal basis for the bailouts, there is a strong implied economic obligation - because it is in everybody's best interest to bail out the weakest state. Just like it was in America's best interest to bail out the banks - as annoying as it was to do, with them paying record profits - the alternative would be significantly worse. Emphasis on significantly.