A Jew brought up among Germans may assume German custom, German words. He may be wholly imbued with that German fluid but the nucleus of his spiritual structure will always remain Jewish, because his blood, his body, his physical-racial type are Jewish. […] It is impossible for a man to become assimilated with people whose blood is different from his own. In order to become assimilated, he must change his body, he must become one of them, in blood. […] There can be no assimilation as long as there is no mixed marriage. […] An increase in the number of mixed marriages is the only sure and infallible means for the destruction of nationality as such. […] A preservation of national integrity is impossible except by a preservation of racial purity, and for that purpose we are in need of a territory of our own where our people will constitute the overwhelming majority.
Ze’ev Jabotinsky (Zionist leader) “A Letter on Autonomy”, 1904