According to Santos Juliá, the main factors that influenced the PSOE government's change of attitude were "pressure from the United States and several European countries; the connection between staying in NATO and Spain–EEC negotiations and the growing favorable stance of the Spanish Defence Ministry to attain closer ties with the Alliance".
Segundo Santos Juliá, os principais factores que influíron no cambio de actitude do goberno do PSOE foron «as presións de Estados Unidos e de varios países europeos; a relación entre a permanencia na OTAN e a incorporación de España á CEE e a actitude favorable a un estreitamento de vínculos coa Alianza adoptada desde moi pronto polo Ministerio de Defensa».