Catalan parliament has deployed a referendum law with +1 MPs, breaking regional Catalan law, silencing opposition and its own constituent powers. The referendum law states that any positive result from the referendum will result in a declaration of independence, with or without agreement with the central government.

Trying not to be get too biased, I'd conclude that Spanish central government is trying to protect the rule of law, state-wide or regional-wide, while also protecting those who didn't vote for separatists parties, which in 2015 elections were 52%.