GOP presidential candidates have overreacted to Vladimir Putin’s move to aid the Syrian establishment. The no-fly zone recommended by many Republican hopefuls risks the possible death of Russian servicemen. But are the stakes so high in Syria that a U.S. president should risk war with another great power? As in the case of another nearly forgotten civil war, the answer is again no.

Americans should view the fighting in Syria as a smaller-scale replay of the Spanish Civil War, which tore apart that country from 1936 to 1939. Waged between authoritarian rebels under the leadership of General Francisco Franco (the Nationalists) and a mix of pro-government left-wing factions (the Republicans), the war cost 600,000 lives. It also revealed how combatants, more than foreigners, determine how civil wars begin, progress, and end.

Spain was an impoverished country in the 1930s, and the economic strains of industrializing during a depression caused a great deal of political turmoil. Inflammatory rhetoric and political assassinations convinced right-wing Spaniards that the Second Republic intended to start a class war. After weeks of planning, a military coup was initiated on July 17, 1936.

The military’s uprising faltered when left-wing citizens helped defeat the rebellion in five cities in eastern Spain. The government armed trade unions, taxi drivers crashed their cars into machine gun-nests, and revolutionary anarchists took over Barcelona.

What energized ordinary Spaniards to support the Republic? As in the case of those who wish to overthrow Assad, it was not some abstract love of democracy. George Orwell, a volunteer in the conflict, noted the source of the ardor in his book Homage to Catalonia. “It was the kind of effort that could probably only be made by people who were fighting with a revolutionary intention – i.e. believed that they were fighting for something better than the status quo.”

Like those who oppose Assad’s regime today, the Spanish Republicans needed this fervor on their side to overcome the factious nature of their supporters and the realities of fighting a conventional war. Its military counted loyal soldiers, liberal democrats, Catalan separatists, anarchists, communists, and international volunteers among its ranks. Ideological divisions aside, the “Popular Front” was ill-equipped to win a conventional conflict. As British historian Antony Beevor noted in his book The Battle for Spain: The Spanish Civil War 1936 – 1939, the insurgents held advantages in manpower, weaponry, and military experience. Yet crucially, the Nationalists were ideologically cohesive. As conservative Catholics, monarchists, and authoritarians, they were likely to hang together in a prolonged conflict.

Foreign intervention doubtlessly worked against the Republic. The Nationalists began receiving aid from Nazi Germany and Fascist Italy as early as late July of 1936. Throughout the war, the German Condor Legion bombed Republican military positions and Spanish villages (Guernica most infamously). On the ground, 50,000 Italians bolstered Nationalist ranks. By contrast, the western democracies imposed an arms embargo on both belligerents. In reality, this decision only impacted the Republic. Not only was the Republic forced to purchase weapons from the USSR, its act of doing so reinforced Nationalist claims that the Republic was a Soviet stooge.

But the Republic also suffered greatly from unforced errors. Its persecution of the Catholic Church during the “Red Terror” handed the Nationalists ample material for propaganda. Stories of gratuitous violence against priests and nuns, some of which was true, helped discredit the Republic in the eyes of the western democracies. The U.S. Ambassador to Britain Joseph P. Kennedy Sr. counseled President Franklin Roosevelt against aiding the Republic. According to Kennedy, many American Catholics wanted Franco to win. He and others got their wish in April of 1939 when the Nationalists captured Madrid.

Aside from a few books, the Spanish Civil War is no longer remembered today, illustrating the often inconsequential nature of civil wars in backwaters. Franco’s establishment of a totalitarian kingdom in the Iberian Peninsula did not impact the security of any great power. In a fitting irony, Franco thanked his patrons in Berlin and Rome by staying out of World War II.

The civil war in Syria has not approached the level of carnage once seen in Spain. Moreover, it is not clear that Putin possesses sufficient resources, both military and economic, to sustain Assad’s war effort, let alone help him achieve victory. After nearly five years of war, the government in Damascus remains locked in a stalemate with the rebels. Much like Hitler and Mussolini before him, Putin will not receive a lot in return for backing one side in a destitute country’s civil war.

The Syrian Civil War is being waged between parties who do not pose a meaningful threat to American security, and for reasons that do not jeopardize vital U.S. interests. The conflict will only become a world war by proxy if politicians insist on making it one.

Tim Reuter writes from Washington, D.C.