Well, the fact that many of us have Jewish ancestry is known (you only have to see “House” and check that the character having closer to an average Spanish apparence is Taub). It is also known how the Spanish Socialist party regained power through a terror attack very similar to an operation of the secret services (see Bologna massacre) behind which lies probably the Catalonian far right. An attack that was demagogically manipulated, using all the Spanish media in the hands of the oligarchy: it is not a surprise that they are manipulating again terror attacks and promoting antisemitism in order to get and advantage (blame the Spanish economic crisis on international actors.) That is normal in Spain, they regained power through a coup and they will do anything -anything- to avoid losing it again.
Regarding the question of the expulsion of the Jews, the Catholic kings acted against such disruptions of internal order in the same way the English and French have done before them. They were creating a State, and a State is defined by the monopoly of violence. They could not tolerate rioting, especially virulent since 1391, and they could not tolerate attacks against Jews, because, according to Feudal laws, Jews were the property of the King: each time this happened, the authority of the King was eroded.
The moriscos -Muslims said to be converted- were expelled in 1609, after one century trying to absorb them. Cryptojews -Jews said to be converted- could not move out of Spain until around 1590. They went then preferably to the Low Countries. However, they no longer lived segregated, as during the Middle Ages: they went in smaller numbers and fully integrated in a society that had evolved enough to admit them. (Segregation was one of the causes of rioting making them an easy target.)
Some authors estimated the Jew population converted during the century of persecutions (1391-1492) and the expulsion in 100,000 people, in a population of 6 million Spaniards.
Other 100,000 Jews moved out of Spain in 1492 (estimated figures).
The expulsion effectively terminated the ferocious popular Spanish antisemitism until modern times (the foundation of the State of Israel and the Arab wars). It can only be traced back in the use of some words.
Sefardic Jews can seek the Spanish citizenship since 1924, by a law approved by General Primo de Rivera. This allowed diplomat Sanz Briz to save 5,000 Jews from Budapest during the WWII. Some came from Greece (if the Nazi forces let them reach the Spanish embassy in Athens to apply for it). Unfortunately, for many Sefardic Jews this law was unknown (it was never publized).
General Franco knew what Sanz Briz was doing and let him do so (the same did not happen in Portugal). Franco’s stance against the Jews was the same the Catholic Church had (that they were religiously mistaken), until this changed in the Second Vatican Council in 1965. There was no “racial” issue against them. However, Franco’s support to Hitler and the necessity of Spain in those years to have good relations with the Arab world prevented foreign relations with Israel. Nevertheless, conservative Jews recognize Franco’s tasks in saving +50,000 Jews who fled from Nazi occupied territories through Spain during WWII.
