With the recent escalation of Russia’s war on Ukraine, tens of thousands of foreign fighters have flocked to the region. While the widespread praise for individuals supporting the Ukrainian defense effort is understandable, governments should take measures to prevent their citizens from joining the war. Foreign fighters epitomize the privatization of wars, and the multiplicity of individual motives and aims contributes to the conflict’s complexity. The involvement of third-country nationals also has the potential to escalate the conflict further. Lastly, Western countries will have to deal with returnees who are better trained, traumatized, and potentially radicalized.