In May 2013, the famed Spanish novelist Juan Goytisolo wrote a column noting the parallels between the Spanish civil war of his childhood and the ongoing Syrian conflict.

"History is repeating itself and brute force is overwhelming ethics," he wrote.

The way the international community was sitting arms-folded watching the "daily martyrdom of the Syrian people", Goytisolo observed, echoed France and Britain's refusal 70 years earlier to intervene in Spain. The democratic states' inaction and attempt to appease Adolf Hitler would prove morally and strategically disastrous as it only emboldened Nazi Germany and Fascist Italy, setting the stage for World War II.

As Syria's civil war has grown more internationalised, drawing fighters from around the world, other proponents of intervention have made this argument: that a hands-off Syria policy has allowed "fascist" movements like ISIL to metastasise - comparing the abandonment of Syria to the desertion of the Spanish Republic in the 1930s.

Spanish civil war

Opponents of western interventionism, on the other hand, have drawn a different lesson from the Spanish civil war, seeing the attempts of Gulf states and their western backers to topple the Assad regime as akin to the efforts of Nazi Germany and Mussolini's Italy to undermine the Second Spanish Republic, the democratic government that ruled Spain from 1931 until it was overthrown by Franco in 1939.

At any rate, the Syria-is-Spain debate took a new turn last week when a video surfaced showing two Spaniards who had travelled to Syria to join the "revolutionary" Kurdish struggle against ISIL.

The young men, appear in front of a Soviet flag and the tri-colour flag of the Second Spanish Republic, and address the camera dressed in military fatigues, with their faces covered. One of the fighters, identified by his nom de guerre Paco Arcadio, declares: "We are not fighting against Muslims, but against the fascism that Islamic State [ISIL] represents, in the same way that people fought in Spain in 1936 or in Stalingrad in 1943."

Spanish intelligence stumbled upon the seven-minute video on a pro-Kurdish YouTube channel, and are now trying to identify the fighters and find out how many Spaniards have gone to fight ISIL. The Spanish volunteers are members of a far-left group called Reconstrucion Comunista (Communist Reconstruction).

Arcadio told the Spanish daily El Pais via telephone that they had joined a battalion made up of foreign fighters based in the city of Ras al Ayn near the Turkish border, under the leadership of the Kurdish People's Protection Units (YPG), a militia fighting both ISIL and the Assad regime. They had learned about the decades-old struggle for Kurdish autonomy from Kurdish nationalists in Spain.

We will fight until there is just one bullet in the magazine, which we'll use to make sure they don't take us alive. We're not going to give ISIL the pleasure of executing us in public. Paco Arcadio, Spanish fighter

But although fighting alongside Kurds, Arcadio was quick to explain that, "This is not a fight against Islam, but for peaceful coexistence between different cultures, and not just in favour of the Kurds, but all humanity."

'International proletariat'

The Spanish volunteers insist that the struggle against ISIL is in the interests of the "international proletariat".

"I appeal to comrades around the world to show their active solidarity," he says.

By various accounts, thousands of youth from Europe and elsewhere have gone to fight for ISIL. A much smaller number of volunteers have also joined the Kurdish struggle against the jihadi movement.

In 2012, the YPG, the armed wing of Kurdish Democratic Union Party (PYD), began presenting itself as a modern-day version of the International Brigade that fought against Franco's forces in Spain - but it has attracted barely 100 fighters.

In the video, after the Spanish fighters finish speaking, German and Turkish volunteers address the camera, and explain - in their native languages - why they have joined the fight against "the Fascist beast of ISIL".

Europeans and an Australian have died fighting the jihadist movement. In early March, a Briton - a former Royal Marine named Konstandinos Erik Scurfield - was killed fighting for the Kurdish YPG. A week later, a German woman named Ivana Hoffman (known by her war name Avasin Tekosin Gunes) died fighting for the Turkish-Kurdish communist group Marxist-Leninist Communist Party (MLKP).

From Ceuta to Syria

About 70 Spaniards are believed to have left to fight alongside ISIL in Syria, mostly young Muslims from the Spanish enclaves of Ceuta and Melilla in North Africa. But these two young leftists represent the first instance of Spaniards being discovered fighting against ISIL, and it is not clear how the Spanish government will respond.

Prime Minister Mariano Rajoy has introduced a new anti-terrorism law backed by the Popular Party and the Socialists that aims to target extremists and jihadist recruiters in Spain - but it's not clear now if young Spanish Marxists hoping to fight against ISIL for Kurdish groups (not on Spain's terrorism list) will also be prosecuted by this law.

Several commentators have observed, what the Spanish anti-ISIL fighters lack in military experience, they make up for in ideological fervour.

Arcadio says in the video that now is the time to strike against ISIL, because the group is "demoralised" after being forced out of the Syrian city of Kobane and Tikrit in Iraq.

He adds matter-of-factly, "We will fight until there is just one bullet in the magazine, which we'll use to make sure they don't take us alive. We're not going to give ISIL the pleasure of executing us in public."

Hisham Aidi teaches at Columbia University. He is the author of the critically acclaimed Rebel Music: Race, Empire and the New Muslim Youth Culture, a study of black internationalism and global youth culture.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.