At the last stages of the Thirty Years' War, the Iberian Peninsula and the Habsburg monarchy that controlled it was in disarray. The Portuguese, alongside the Catalans, revolted around the year of 1640 with assistance from the French and Dutch.
At the same time as these two rebel factions were taking hold of portions of Iberia, there was a conspiracy, headed by the 9th Duke of Medina-Sidonia, Gaspar Alonso Perez de Guzmán, which aimed to free Andalusia (southern Spain) from the Castilian yoke. However, the conspiracy, unlike the ones in Portugal and Catalonia, never made it past the planning phase, due to internal betrayal, the refusal of the most important parts of the Andalusian nobility to participate in it, and the failure of the Dutch and French fleets to arrive in time to support Guzmán.
But what if most of these problems had been mitigated from the start, and the planned Andalusian revolt had gone through? I think that Guzmán could attain the support of the lower nobility, the popular Andalusian masses, and the cristianos nuevos (former Jews) who exercised a significant ammount of control over the trade relations of the Iberian Union. Could the rebellion succeed in creating an independent Andalusian kingdom?
If Castille's connection with the Americas is severed due to the Andalusian rebels capturing the important port of Cádiz, what are the effects?