Catalan President Carles Puigdemont is moving forward with a referendum vote on independence on Oct. 1. It's a controversial move, considering he's trying to rush it through parliament with a simple-majority vote and the law mandates that if those in favor win, Catalan will be independent within 48 hours of the vote, per The Economist.
Not so fast: Spain's prime minister, Mariano Rajoy, has vowed to veto the vote and even says it's illegal.
Why: Spain's constitution of 1978 (which is supported by more than 90% of Catalans) bans secession; the official language refers to "the indissoluble unity of the Spanish nation." Any referendum has to completely comply with the constitution, and Puigdemont's does not.