AP Photo

With every passing week, the Syrian conflict increasingly resembles the Spanish Civil War. The images of warplanes bombing civilians and destroying cities have turned Aleppo into a latter-day version of Guernica, immortalized in Picasso’s masterpiece. But the real similarities between the two conflicts are to be found in the behavior of the international community’s main actors, which have again taken opposite sides.

On one side stand Russia and Iran, cynically determined to buttress President Bashar al-Assad’s regime. On the other side stand the established democracies, hesitant and ambivalent in their support of the rebels. In 1930’s Spain, of course, Nazi Germany and Fascist Italy fully supported General Francisco Franco’s rebellion, while the democracies...