Booklady,
A lot.

Wolf,
I confess I'm a little surprised you ask that question; quite a few times, some "posters" "talk" about this or that being unconstitutional, usually referring to actions that the "Madrid Government" (by that you mean the Spanish Government, right?) undertake. So I thought everybody was such an expert on our constitution here!
By law, in Spain referendums can't be carried out locally, if there was a referendum about the indepencence of the Pais Vasco we would all vote. The PNV wants to change the constitution beforehand so only the Basque people would vote.