Ukraine is not the first place to come to mind when the term "foreign fighters" is used.

But this Eastern European country has long been a destination for men from Western countries seeking the thrill of a battle they view as a fight for the future of Europe.

As we saw in the wake of last month's terrorist attack in Christchurch, these radicalised young men in the West are not just "keyboard warriors" but committed ideologues with increasing desire and means for violence.

And like former Islamic State fighters and their families who hope to return to Australia after the fall of the caliphate, it is important to understand what motivates these young men to leave Australia to fight in a foreign conflict in Ukraine.

War in Ukraine: the basics

Since 2014, Ukraine has been embroiled in a civil war after two regions in the east of the country declared autonomy. Thousands of foreign fighters from all over the world have flocked to the area, collectively known as Donbass.

Depending on their political views these fighters — from Western Europe, Canada, the United States and Australia — join either the ultra right-wing battalions of the Ukrainian forces or the left-wing Russian-backed separatists.

Last week ABC News broke the story of five Australians who had been fighting with the Russia-backed separatists in this conflict and now want to come home.

The story noted the role of extremist right-wing ideology. But that is only half of the story: far left radicals have been drawn to this war, as well.

How conflict in Ukraine mirrors the war in Syria

For the past three years I have been researching the motivations of foreign fighters in Ukraine and trying to understand what drives them to join the conflict.

Ultra-nationalists and far right-wing ideologues come to support Ukraine against the influence of communism and what they view as the threat of a neo-Soviet Russia.

Anti-imperialists, anti-fascists, and those on the far left come to defend the pro-communist separatists and defend the autonomous regions from what they see as global imperialism.

For both the far right wing and far left, the battle for Ukraine duplicates the issues driving the war in Syria: it is a fight between the US and Russia, or "Western values" and communism, or between "Western imperialism'" and "true" freedom and democracy — depending on your ideological stance.

This ideology mirrors that in Syria but is being fought on a different front line.

"I literally flipped a coin between going to Syria and Ukraine," one recruit said. ( Bryce Wilson )

Voices from the frontline

In my research, I spoke with foreign fighters on each side.

While their motivations for joining the fight differ greatly, the foreign fighters on each side of this conflict bear a striking resemblance — young, male, politically charged and with previous experience in the armed services.

Men on both sides see the war in eastern Ukraine as one of the front lines in a global war between competing ideologies.

The foreigners I spoke with on the left wing separatist side saw NATO expansion into Eastern Europe as a tentacle of a malignant US global imperialism, and saw defending the People's Republics in Donbass as a means of fighting this hegemonic global order.

Peter*, an anarchist from Russia who fought with the separatists, told me: "Almost everyone went there expecting to fight pro-American fascists".

Another fighter from American who I will call Rich characterised the war as "a war between normal people and fascists".

A Ukrainian scout watches over a strip of no man's land between Ukrainian government positions and those held by the Donetsk People's Republic. ( ABC: Bryce Wilson )

Meanwhile, George, an American fighting on the Ukrainian side, described those he fought with as having "the same hatred for Russia or the same kind of sense of nationalism".

Though the men in George's battalion came from various countries, including Britain, Germany, Austria, Canada, and the Netherlands, they shared a belief that the outcome in Ukraine would have domino consequences across Europe.

Luke, an American who volunteered with the Armed Forces of Ukraine, said:

"What is going on in Ukraine now is really a fight for the future of Europe. Depending on which round Ukraine goes will decide a lot of what will happen in Europe in the future".

For men on the right, defending Ukraine from "Russian invasion" was a necessary step in curtailing a malignant political force and defending Western values.

Shopping around for a fight

Given their ideological motivations, most of the foreign fighters I spoke to in Ukraine had been in or attempted to fight in other wars, including Syria.

George first tried to join the French Foreign Legion, but when he was unsuccessful, looked for other opportunities to participate in war.

"I literally flipped a coin between going to Syria and Ukraine," he confided.

Lance and Rich both contemplated fighting in Syria before choosing to come to Ukraine, but Lance ultimately decided against it as the Kurds were communists.

Nearly everyone I spoke to had a background in their own country's armed forces and had served in an active combat zone, like Afghanistan or Iraq.

For a lot of the men, it was the thrill of battle that lured them back, and the belief that the cause in Ukraine was more justified than "defending some goat herder in Afghanistan".

Peter noted the enjoyment he felt when fighting, that "it must be an addiction".

George, now back in the US after fighting in Ukraine, recognised that "regular" life is just not as fun: "I'm working an OK job, you know. My life is not super interesting or anything, but if you tell me 'Hey, five minutes from now you can be knee deep in the bush in Africa fighting the civil war', I'd sign up."

But, given the romance of fighting, many foreign fighters quickly experience disillusionment when they realise that their view of the world didn't quite match reality on the front lines.

"I got bored with it, all this opposition of right wing and left wing people," Peter explained. "I found friends among the enemies and I got to understand that it was all just a game."

When the romance of war wanes, one pathway out was seeking another conflict.

George and Lance both eventually bored from the lack of combat in Ukraine and left to fight for a warlord in South Sudan, but were detained by authorities and deported back to the US.

Lance later travelled to Venezuela, but soon decided "Venezuelans are cowards and do not deserve to be saved".

Will these fighters bring their wars home?

Given that the pathways into this war have been predominantly through extremist political online associations, there is reason to worry about this war being brought home to Australia.

Two Australians who returned from Ukraine in 2018 have ties to right-wing extremist groups like the Right Wing Resistance.

These links point to not only the polarisation of politics here in Australia, where violent clashes have frequently occurred between far right-wing groups and so-called "antifa" groups, but also to a transnationalisation of these extremist politics.

The terrorist attack in Christchurch proved the extent of the danger extremist ideology can pose.

We cannot treat foreign fighters from Australia, then, as autonomous adventurers, but as a symptom of a deeply divided society with the potential for serious domestic ramifications if not systematically addressed.

Furthermore, demonising one side of the polarisation — the right-wing extremists — while ignoring the parallel politicisation of the left may only serve to further entrench ideological divisions and the commitment of right-wing extremists to perpetrate violence.

Stopping young men from going abroad to fight in foreign wars will entail more than laws criminalising the actions, but also a deeper societal shift to challenge the influence of simplified narratives, mythologies, and perceptions of politics that have shaped the individual motivations to fight.

* Names have been changed throughout.

Sara Meger is a lecturer in international security at the University of Melbourne.