A Socialist Spain in 1909?
I was reading a bit around, and I came upon an interesting idea for an alternate timeline: the Semana Trágica. It was a conflict between the far left and the military in 1909, leading to a lot of bloodshed. I have two questions:
What PoD could have plausibly caused the Semana Trágica to result in a successful overthrow of the Kingdom of Spain?
And how would a socialist Spain have reacted to the unfolding events of WWI?