From defending Spain's interests within the EU to its tortuous relations with Morocco, there will be no shortage of foreign policy challenges for right-wing leader Alberto Nunez Feijoo if he wins the July 23 election.If elected, Feijoo -- who would take over during Spain's turn at the head of the EU presidency that began on July 1 -- would have to reassure Brussels about several worrying issues, notably if the far-right Vox enters government.