The EU legal system has a great importance on the Spanish one, as it must be followed in the country. The international treaties, once validated, become part of the internal regulation of Spain.
However, although it exists a transfer of competences from Spain to the EU the Constitution also extends the limits of that transfer. These limits are related to: the State sovereignty; the Spanish constitutional structures: and the ential values and principles consecrated in the Constitution.
Anyway, the jurisprudence of the European Court of Justice and the European Court of Human Rights must be accomplished in the country. (Moreno Bobadilla 2016)