Résumé : We demonstrate that there is no legal way under current EU law to adopt a citizenship-based ban on entering the Schengen zone. The de facto national-level ban against the Russian citizens introduced by Poland, Finland and the Baltic States breaches EU law. Further, amending the law to allow for a citizenship-based ban goes against the core values the Union is based upon, pitting populist proposals against the Rule of Law. References to ‘wholly exceptional circumstances’ would not help either. Any proposal to ban Russian citizens would include dissenters and deserters unwilling to contribute to Putin’s war from seeking refuge in EU territory and imply impermissible discrimination on a handful of grounds. It is no surprise that such a proposal was defeated in the Council, following which the Baltic States, Poland, and Finland have implemented such a nationality-based ban on entry at the national level in breach of EU law, using Russian citizenship as a ground for refusal of entry within their borders. Central to the citizenship-based travel ban is a replacement of reason required by the Rule of Law with randomly assigned retribution, prima facie unrelated to any legitimate aim that could be achieved by the measure. The replacement of the Rule of Law with retribution, in turn, counterproductively strengthens Putin’s totalitarian regime as well as, directly, its military: those unable to flee to Europe may well end up being conscripted for Russia’s war of aggression. Such a de facto ban, even if outright unlawful, is difficult to repudiate and reverse, which makes it imperative for other Member States as well as the institutions of the Union to put sufficient pressure on the violators to save the Schengen system from unlawful populist fragmentation. The Union’s strength is precisely in its inability to act along the populist lines the ban implies, rather than one of its weaknesses, as conveyed by the alarmist agitation of some Member States. We demonstrate that the whole debate around the blanket citizenship-based visa and entry ban, as well as the Union’s de facto powerlessness in the face of Member States’ arbitrary replacement of the law with hateful citizenship-based retribution is a stress-test of the Rule of Law in the EU.