As there were Catalans and Basques fighting for their own causes in Spain, in Syria today are Kurds, Druze and al-Qaida with their own rival agendas.
As America and Britain stayed out of the Spanish Civil War, so today America and Britain have stayed aloof from Syria's conflict.
As the Spanish Civil War exposed the impotence of the League of Nations, Syria's conflict is exposing the paralysis of the United Nations, when permanent members of the Security Council like Russia refuse to authorize the kind of intervention they did in Libya.
As the Spanish republic received moral and material support from Moscow, today Moscow sends attack helicopters to Damascus, while Turkey provides sanctuary for the resistance, and Saudi Arabia and Qatar provide weapons.
Russia and Iran see Assad's Syria as their last strong, reliable ally in the region. Syria's ports on the Mediterranean are open to Vladimir Putin's navy. And Putin's military-industrial complex has long sold the Assad family the weapons to fight its wars and crush rebellions.
If Assad's regime were to collapse and the Muslim Brotherhood come to power, Russia would be virtually out of the Middle East. Iran would be almost isolated. Had we not overthrown the Sunni regime of Saddam and brought the Shia majority to power in Baghdad, an Iran without Syria would be an Iran without a major ally across the region.
The first peril in the Syrian conflict is that it could become a civil war in which not just 10,000 die, but scores of thousands perish.
A second danger is that as Syria contains Sunni, Shia, Druze, Kurd, Arab, Christian -- indeed, mirrors the Middle East -- a Syrian civil war could become a proxy war for all in the region, beginning with Lebanon.
Third, as Syria is aligned with Iran in the conflict with Israel and with Russia on the world stage, greater powers may come to see themselves as having a vital stake in how this war ends, and intervene, each in its own way, to assure a favorable outcome.
The Spanish Civil War ended in Franco's victory in 1939 and ended well for the Western democracies that had not intervened.
When Hitler, after occupying France in 1940, met with Franco to ask permission for the Wehrmacht to cross Spain to attack Gibraltar, Franco said no and put troops in the Pyrenees to enforce his decision.
Unlike Mussolini, Franco remained a nonbelligerent in the world war, returned U.S. pilots who came down in Spain and agreed to a postwar alliance with the United States.
Non-intervention in the Spanish Civil War worked out just fine.