Oh Vey! Fascists!
Thank you for your quality threads, but I think you forgot to integrate the historical background without one can not understand the Spanish Civil wars and the political situation this all played in. Biggest failure is to name the foreign meddling into this affair.
OK, the whole trouble started with the Spanish war of Succession, when a (Italian French) Bourbon should replace the late Habsburgian king.
The Bourbons were in French fashion to abolish the local rights and create a central state. That didn’t go well especially with Basques and Catalans who did support a Habsburgian alternative as Spanish king.
The Basques and latter Carlists were a particular conservative and Catholic people that opposed the (((liberals))) and their (((enlightenment modernising))).
Basque nationalism as an independence movement and the foundation of the Basque National party is a British psy-op of the 19th century when its founder went to study in Britain to “discover” that the Basque are a “total different people” than the rest of the Spanish.
Unsurprising the symbol of this movement looks like the British flag.
Northern Spain was then under strong influence of Britain (more than already regular) due to the influence of British financed and modelled industrialising.
It is important that the founder of Basque nationalism was a unashamed racist and many Basque still follow his ideas (even if he was factual incorrect and goaded by the Brits).
Another point is that France lusted since a long time to annex Barcelona. French Occitan originally a similar culture and language as the Catalans had. Navarre, the original Basque kingdom was absorbed half by France after the French revolution and half by Spain.
Fast forward to the last Spanish Civil war that was won by Franco with the help of Britain. In fact the British started the war by flying Franco out of the Canary island to North Africa and his troops.
While the Britain supported in secret Franco, publicly they were the biggest enemies of him and are the source of the most influential anti-Francoist, anti-Spanish propaganda through its publishing houses and universities, particularly its history departments, such is the duplicity of the British.
The (((French communist))) regimes before and after the war were the biggest enemies of Franco, more than the Soviets.
It was no accident that ETA found refuge in France and the decline and dissolving of ETA happened when France, very late, did withdraw its support. Most armament depots, safe houses, hiding place for kidnapped person and source of its explosive were in France.
One can say that ETA was a French anti-Spanish secret service operation.