Serbia is handing out passports to Russian nationals at a pace that should alarm every European capital: four times more Russians than all other foreign nationals combined this year, with sanctioned figures reportedly included. This is not routine paperwork. It is a back door into Europe. Visa-free access cannot become a loophole for blacklisted networks. Belgrade must choose: credible EU path or convenient ambiguity with Moscow. Europe must respond with scrutiny, not naivety.