​The dilemma of foreign fighters returning from war zones like Chechnya and Afghanistan, as well as those associated with terrorist groups like ISIS and al-Qaeda and those participating in the first Russian-Ukrainian conflict in 2014, severely affected the majority of European countries. The problem has sparked a public and political controversy by fostering an atmosphere of uncertainty and insecurity. Having gained high combat skills and vast communications, most returning foreign fighters have a tendency towards violence. Some even committed terrorist crimes that shook the European society and the whole world.

Controversy Reignited
With the outbreak of the Russia-Ukraine war in February 2022, controversy flared again over the fate of returning foreign fighters and its impact on Europe's security, especially when both sides of the conflict seek to recruit the largest number of foreign fighters, and Kyiv having announced the formation of an international corps specifically for polarization. Reports show that 17,000 foreign fighters joined either side of the conflict, which should trigger security alerts and prompt clear plans to deal with those fighters after their return.

In October 2020, the Vilnius institute for Policy Analysis focused on this issue and published a book by Egle E. Murauskaite, a researcher in political crises and their implications on Europe's security, which tackled the European experience with foreign fighters returning from the first Russia–Ukraine war in terms of the profiles and patterns of those fighters, the risks of their return, and how Europe handled the risks. To learn from the experience and avoid future risks, here are some key highlights form the research.

​Patterns of Foreign Fighters
Foreign fighters are categorized into four types:

  1. Veterans with Historical Grievances: These are fighters who hold grudges against Russia and seek revenge for past defeats of their peoples. Among them are Chechen fighters who revived the “Sheikh Mansur" battalion that had fought earlier in Chechen wars against Russia, then scattered throughout Europe. They reunited in Ukraine to fight the Russians. Other Chechens joined “Aidar's" battalion, working directly for the Ukrainian Ministry of Defense. This particular group of foreign fighters, however, primarily came from Moldova and were motivated to fight for the pro-Russian side by anti-Ukrainian sentiment as a result of Kyiv's support for the Transnistrian enclave's independence in 1990 and its military intervention using volunteers and Cossacks. Notably, some Ukrainians who had emigrated to Europe and America and were motivated by anti-Russian sentiment made the decision to go back and fight the Russians there.
  2. Disillusioned Ideologues: Right-wing fighters were pro-Ukraine, while left-wing, anti-West fighters were pro-Russia. Rightists believe that Western governments and institutions failed to face dictatorships, as in Syria. Fighters from Lithuania, the Baltic, and Poland joined the Ukrainian side to stop the Russian expansion. Meanwhile, fighters from Sweden, France, Italy, Germany, and Austria came to fight on the pro-Ukraine side for the “survival of white people". However, the ideologically motivated foreign fighters on the pro-Russian side view the conflict in Ukraine as essential to ending NATO and the West's control over Russia's sovereignty in Eastern Europe. Due to their historical sympathies for communism in opposition to liberal Anglo-Saxon globalism and the decadent West, fighters from France joined the pro-Russian side.
  3. Opposition: The majority of the armed opposition joined the pro-Ukraine side in order to destabilize Putin's regime. Most of them fled their countries due to their political opposition to pro-Russian regimes or to seek retribution for themselves or their families who had been persecuted for their political beliefs. Others see no other way to achieve democracy in their countries than through external armed conflict, particularly after the domestication of internal opposition.
  4. Fighting for the Sake of Fighting: This category includes experienced foreign fighters, who come to join one conflict after another, as well as civilian adventurers curious about fighting.
Concerns and Lessons Learned
Here are some major concerns over foreign fighters returning from the Ukrainian war:​
  • Self-radicalization: This is less likely given that the Russia–Ukraine war is a guerrilla war or a hybrid war which has not witnessed any suicide bombings like those carried out by extremist organizations. Furthermore, despite numerous arrests of returning foreign fighters, there are definitely no regional or international organizations in Ukraine identified as extremist organizations. Instead, most foreign fighters in Ukraine tended to already hold more extreme political views before joining the fight, and they were often already on the local law enforcement radar in their homeland.
  • Recruitment Figures: This concern stems from using returnees as heroic candidates for recruitment. This seems to be a somewhat valid risk in Ukraine given the huge influence of social media on recruiting many of those prominent fighters, who become role models.
  • Relationships Forged during Battle: The risk worth monitoring is the pattern of relations that arose as a result of the Ukrainian war. The failed 2016 coup in Montenegro was one example; the plot to assassinate the prime minister on election day included several right-wing extremists who had fought in Ukraine, as well as two GRU agents from Russia. Returning fighters in the disillusioned ideologues category would be of particular concern because they are more likely to engage in militant activity and networks, potentially leading to anti-government or anti-minority plots. Furthermore, pro-Russian fighters would be of greater concern if they had been recruited in other conflicts by specialized enterprises, such as Wagner, which is involved in conflicts in Russia, Libya, and Africa.
Past Experiences
Most European countries used punitive measures to deal with foreign fighters returning from Ukraine, ranging from reprimands and fines to lengthy prison sentences. Ben Stimson of the United Kingdom was the first EU citizen to face punishment for fighting in Ukraine; his support for the pro-Russian side was classified as assisting acts of terrorism, and he was sentenced to 5 years in prison. Some concerns have been raised about the discrimination between Russia's and Ukraine's supporters. The UK authorities responded that each case would be judged on its own merits, based on the actions of individuals on the battlefield and the evidence available.

Meanwhile, in the Czech Republic, some returning fighters were charged with terrorism for their involvement in Ukraine's pro-Russian separatist campaign, with sentences ranging from 5 to 20 years in prison. Spain was yet another prosecutor of its citizens fighting on the pro-Russian side, apprehending eight foreign fighters in 2015 on charges of possessing arms and explosives, complicity in murders, and endangering Spanish security. However, due to a lack of supporting evidence, most of these charges were dropped.

In 2015, Italy passed an anti-terrorism law that stipulated prison sentences ranging from three to ten years for anyone accused of fighting abroad. By 2018, up to 20 Italians had been arrested on suspicion of recruiting fighters for the Ukrainian conflict, mostly neo-Nazis fighting on the pro-Russian side, and 25 others had been detained for questioning. Italy appears to be treating these fighters selectively; among those prosecuted for fighting on the pro-Russian side were Lega Nord members. Meanwhile, Italians fighting on the Ukrainian side received legal protection from Ukraine based on their legitimate legal status during the fight.

In contrast, Belarus sued all returnees from Ukraine, both combatants and noncombatants, labelling them "mercenaries." This stance stems from the belief that the returnees are deemed "opposition" to the Belarus regime. Serbia had filed criminal charges against 45 men for fighting on the pro-Russian side by mid-2019. Given the diplomatic crisis between Serbia and Ukraine, the majority of the accused were sentenced to six months in prison before having their sentences reduced, dropped, or suspended.

Poland has officially denied any presence of its citizens among the fighters in Ukraine, while at the same time prosecuting any returnees. Slovakia, however, denied any presence of Slovak fighters in Ukraine, but condemned such behavior. Meanwhile, the Baltic states handled returning foreign fighters differently. Estonia, for instance, extradited some of its ethnic Russian citizens to Ukraine on terrorism charges, and Latvia chose to prosecute its returnees for lesser charges.

Overall, it is clear that official Western prosecutors' strategies for dealing with fighters who have just returned from Ukraine are marred by ambiguity and misalignment. This contrasts with the obviously adamant stance taken in pursuing the fighters who have returned from Syria or Iraq on terrorism-related offences. It is noteworthy that the majority of individuals apprehended by the prosecution were fighters who supported Russia. Pro-Ukrainian fighters' legal standing appears to be more murky, though, as some of them have served in battalions that are officially or unofficially commanded by the Ukrainian Ministry of Defense.

The Fate of Returning Foreign Fighters
Compared to the stories of their fighting experiences, the fate of returning foreign fighters is significantly less frequently documented. Since they typically maintain a low profile upon their return and would prefer solitude had they settled for good, it is challenging to learn about them through personal interviews. The social attitudes they typically encounter are as follows:

  1. Marginalization: Returning foreign fighters, who fought for the Ukrainian or Russian side often suffer from marginalization. For example, an Australian fighter confirmed being constantly labeled as a potential threat to society by local authorities and society activists. The Georgian government with pro-Russian leanings had several fighters persecuted and subsequently relocated in Ukraine or elsewhere in Europe.
  2. Acquisition of Violent Skills: Some foreign fighters appear to have entered the battle with the express intent of developing the requisite abilities to commit violent acts. For instance, in 2017, two Swedish members of the neo-Nazi Nordic Resistance Movement, which is fiercely anti-immigrant, have reportedly gone into Ukraine to train with the pro-Russian side, and upon their return bombed a center for asylum seekers in Sweden. Another comparable case is an American white supremacist who traveled to Europe to celebrate Hitler's birthday, where he met with members of the pro-Ukrainian Azov battalion, and subsequently returned to the US to assault protesters during the Charlottesville rally.
  3. Silencing and Terrorizing the Opposition: Some returning foreign fighters on the pro-Russian side are exploited to silence and terrorize the anti-Russian regime opposition. A notable example is a Slovak pro-Russian fighter who upon his return in 2016 started threatening local journalists with violence for criticizing Moscow for fighting in Ukraine.
  4. Social Support: The pro-Ukrainian Lithuanian warriors claimed that after their return, they received social support that improved their socioeconomic standing. Comparatively, the Serbian pro-Russian warriors who were not criminally charged were neither marginalized nor perceived as a threat in public discourse.
  5. Forming Unions or Associations: Some foreign fighters formed unions or associations on the grounds of “volunteer opportunities from Open Arms Fellowship" such as the Union of Donbas Volunteers, Donbassforeningen (Sweden), and Coordinamento Solidale per il Donbass (Italy), among others.
Ukraine, which has been dominated by extreme right-wing nationalists, has been haunted by the consequences of the first Russian-Ukrainian conflict. Active members had previously fought for fighter organizations like Azov, Aidar, Pravyi Sektor, and others. It is not an exaggeration to argue that this situation may serve as the catalyst for similar movements that may wreak havoc on European politics.