Convergence and Union, the largest of the Spanish PANE and sometimes the third party, played since the restoration of democracy a central role in the governance of the state when the majority party did not have an absolute majority. This is because CiU occupies a central position in the Spanish political system. They treated a centrist party, from the point of view of left-right and moderately nationalist party, a position that has allowed him to support the various minority governments, whatever their political ideology, and sustain fundamental political decisions over time. However, despite the repeated offers received CiU never opted to join the central government, although sometimes it has been a major source of division. It is this sense that the behavior of CiU in the sand that has been characterized as the party of pressure because their behavior is more like that of a pressure group to a political party. However, this willingness to cooperate, even external, seems to be changing from that CiU has recently opted for a strategy openly sovereigntist, a strategy that is generating considerable internal instability. The aim of this paper is to show that the mutation has been experiencing ideological recently CiU is having an impact on their behavior in the national arena and its internal cohesion.
