Ponencia "The PSOE, the strategy of Santillana del Mar, and the birth of UPyD" en el XXIInd World Congress of Political Science: Reshaping Power, Shifting Boundaries; organizado por la International Political Science Association, Madrid, julio de 2012. 
In late summer of 2003, the Secretary General of the Partido Socialista Obrero Español (Spanish Socialist Workers Party) and candidate for the Presidency of the Spanish Government held a Summit in the town of Santillana del Mar, with its known as "regional barons", ergo, the Secretaries General of PSOE in each Autonomous Community (remember that the PSOE is a federal party).
The purpose of the Summit was to define a political party strategy about as it should be positioned in each community and centrally with respect to the nationalist parties and define the model of territorial integration and diversification they wanted to defend. The result was to move from "Spain plural" to "Spain different" (in Spanish "de la España Plural a la España Diversa), after the closed defense the Partido Socialista Catalán (Catalan Socialist Party) leader Pasquall Maragall made of the concept of asymmetrical federalism. That broke the line that the party had maintained until then: territorial solidarity.
The objective of this paper is to analyze the implementation of this strategy and the results it has offered to the party, taking particular account of some significant milestones such as excision of members and people close to the party that preferred a more united and cohesive Spain, who founded Unión, Progreso y Democracia (Progress and Democracy Union party).