I'm not sure I understand your point. Do you think the majority of spaniards would support amending the constitution to allow for a region to declare independence? Seems really dubious to me. And if not, then why blame the constitution?

I mean a Constitution is not, and must not be, respected if it goes against the will of a big part of the population.

A state constitution must offer a framework which is interesting for all of its peoples and territories: if big groups of people do not see the point of it, it looses its validity.

No dude, authority emanates from armies, which are never irrelevant. And the writing is on the wall.

I hope the Catalans that voted to leave have really good reasons to do it, because if the situation isn't defused somehow, there are some tough times ahead.

That is true for primitive societies. Modern, civiliced societies do not resort to violence when they lose the war of words and persuassion.

It is not clear we are in a modern era.