Bilbao and Barcelona had some the most prosperous spells in their history during the Franco dictatorship...
In order to prevent the Barcelona board engaging in any separatist actions, the Franco regime insisted, in the immediate post Civil War years, that the President of Barcelona CF was one of their own placemen. Politically, this was actually to the benefit of the football club. For example, as President, the Marquis de la Mesa de Asta, who was a personal friend of the brutal General Moscardo (who was Minister of Sport at the time) and had himself been a Nationalist officer, was able to persuade Moscardo to allow exiled Barcelona players to return to the country. A successor of his, Josep Vendrell, was also a Nationalist Colonel. Both of those did everything they could to ensure the football club's onfield success, they weren't there to weaken it.
When the Marquis, despite his close links with the regime, was pressured by the authorities to resign following the infamous 11-1 defeat at Chamartin, the Madrid president Peralba was forced out at the same time, and for the same reason. As it turned out, that worked out well for Madrid as it led to the visionary Bernabeu taking over.
What's also missed when the signing of Di Stefano is brought up, is that much earlier Barcelona had been allowed to sign the almost as influential Kubala under the noses of Real Madrid, and who led them to one of their most successful eras - so much so that he's often given the credit for the club building the Camp Nou to cope with the increased capacity they needed. As Kubala was a Hungarian exile, the Franco regime had to give him Spanish nationality and lobby FIFA to allow acceptance of it. Hardly the actions of a regime attempting to restrict Barcelona's success.
