Not quite that simple from what I understand. A week before the vote the Catalan parliament passed two laws, one that a referendum should be held and one that if yes to independence won, regardless of turnout, independence would be unilaterally declared. No way that the spanish government could allow that to go ahead unchallenged. Its worth noting that they have allowed nonbonding votes previously, there was one in 2014 with similar results and turnout. Its the fact that this one was binding that caused the crisis. https://www.economist.com/blogs/economist-explains/2017/09/e...