It's been done to a limited extent by Estonia, Latvia, and Lithuania already https://vm.ee/en/news/government-restricts-entry-estonia-russian-nationals-18-augu

It's been done to a limited extent by Estonia, Latvia, and Lithuania already https://vm.ee/en/news/government-restricts-entry-estonia-russian-nationals-18-august https://vm.ee/en/news/government-restricts-entry-estonia-rus... https://www.lrt.lt/en/news-in-english/19/2050380/latvia-to-ask-thousands-of-russian-citizens-to-leave-the-country#:~:text=Following%20Russia's%20full%2Dscale%20invasion,a%20mandatory%20Latvian%20language%20exam https://www.lrt.lt/en/news-in-english/19/2050380/latvia-to-a.... https://www.lrt.lt/en/news-in-english/19/2050524/lithuania-deems-1-164-belarusian-and-russian-nationals-a-threat-revokes-residence-permits-and-visas https://www.lrt.lt/en/news-in-english/19/2050524/lithuania-d... As you can see it can be done, is being done, and ought to be done across the whole of EU given the number of unexplained fires and explosions of factories, warehouses, and shopping centres in Europe, explosives planted in packages sent via DHL, an attempt to assassinate the CEO of Rheinmetal, cutting undersea cables, and disruption of GPS signal used by civil aviation.