I suspect this is something the government should not do. Like putting Hitler on trial, it merely gives them an opportunity in the spotlight to be a rallying point for their cause. The government would be better served by addressing the cause of the “rebellion.” I’d take that cause to be wealth redistribution from the people who now want to leave to voters in poorer areas. Of course, then the government would have to stop giving away so much of Other People’s Money (OPM.) And, that would result in an entirely different set of issues. The politicians are in the position of fighting a fire on a sinking boat.
Breaking up Spain is like breaking up the US. No unity anymore.