I was just wondering what folks think might have happened had the coup plotters managed to keep their crap together and make things a bit more well planned, like capturing and/or assassinating the King, or if he hadn't been alive at the time.
What would've the consequences been had Spain jumped to a military dictatorship in 1981?
It wouldn't be necessary something as far-fetched as capturing or killing the king. If some additional key figure betrays the king and supports the coup until the end and becomes more coordinated, that would work. Setting aside how the king would have reacted (some say he was planning to flee, and I have strong reasons to believe that), the plotters would have gone ahead with or without the king.
What would come later? The plan was, if I recall correctly, creating some kind of national concentration movement, with the "white elefant" as a main head of state (probabily someone like Milans del Bosch or Torres Rojas, we still don't even know who the hell he actually was), and prosecuting the Basque Nationalist, as well as the Communist elements, who still got some political force at the time. What could be expected? If the Basque Conflict was nasty IOTL, state terrorism would reach new levels ITTL, but also directed at leftist groups. I can perfectly picture it as an European version of the rightist dictatorships of Latin America at the time, but without the strategical support of the Western Powers (Reagan condemned the coup, and Thatcher bluntly called it a terrorist act), and with a strong paliamentary makeup. No NATO entrance, definitely no EEC entrance and no Olympic games. It's hard to say how much would it last, but maybe until they screw up national interests very obviously, as in Argentina.
I don't know which effects this would have overall, but it would surely be catastrophic for Spain. After the regime, probabily a third republic would emerge, and Basque and Catalan independence wouldn't look out of place. Spain's EU membership would be substantially delayed, assuming it would happen. Mybe, far left terrorist groups like GRAPO would be still operating.