Basically, have the seven Basque provinces of Spain and France exist as an independent nation by the present-day, with this country being at least as prosperous as the area is today. Bonus points for having the Basque State take additional territory from either Spain or France and/or more Western Europe balkanization. My ideal borders for a "Greater Basque Country" would be the Adour, or if we wanted to get really ambitious, the Garonne, with some border expansion in Spain as well.
The main problem that I see in this scenario is that nobody really has a reason to promote the creation of a Basque state which would presumably need a boatload of foreign help to have a chance at survival. Because of this, said state would probably need to form during one of France or Spain's periodic outbreaks of instability which occurred throughout the 19th century. Once they establish themselves, I can see them being a British ally; of course, even such an alliance would leave the Basques at the mercy of the French.
I say post-1776 POD because this leaves time to influence the French Revolution, which marked the start of the suppression of Basque in France.
The main problem that I see in this scenario is that nobody really has a reason to promote the creation of a Basque state which would presumably need a boatload of foreign help to have a chance at survival. Because of this, said state would probably need to form during one of France or Spain's periodic outbreaks of instability which occurred throughout the 19th century. Once they establish themselves, I can see them being a British ally; of course, even such an alliance would leave the Basques at the mercy of the French.
I say post-1776 POD because this leaves time to influence the French Revolution, which marked the start of the suppression of Basque in France.