Today the Catalans go to the polls to elect a regional parliament. Several parties favoring independence from Spain are offering a joint list of candidates, turning the regional election into a referendum on Catalan independence.
Should they win today, they plan to start a process aimed at declaring Catalonian independence some 18 months from now. Whether Spain is willing to take up arms to defend its territorial integrity is unclear.
Basque separatism from Spain has certainly provoked a muscular response in the past, not so much military as law enforcement-oriented. Will Spain arrest those Catalans taking active steps toward separation? At this point the Spanish response is unknown, perhaps unknowable.
Also unknown is whether Catalans will take up arms in the event Spain stonewalls their independence movement. I predict some will turn to violence, as in Northern Ireland.