Both the Spanish and Bosnian wars mobilized outside fighters along identity lines

Evidence

The Spanish Civil War was a war between political systems and ideologies, the Bosnian War a war between civilizations and religions. Democrats, communists, and fascists went to Spain to fight alongside their ideological brethren, and democratic, communist, and, most actively, fascist governments provided aid. The Yugoslav wars saw a similar massive mobilization of outside support by Western Christians, Orthodox Christians, and Muslims on behalf of their civilizational kin. — Samuel P. Huntington, The Clash of Civilizations and the…, 800

Categorization

• XREF: The Spain-Bosnia parallel resonates with the idea of proxy wars and ideological kinship seen in the Spanish Civil War historiography.