Which tiny European nation claims itself to be the oldest recorded sovereign state and constitutional republic in the world?
Nation state became the Soviet Union after the Russian Civil War. A few of the smaller states survived: the independent principalities of Liechtenstein, Andorra, Monaco, and the republic of San Marino. (Vatican City is a special case. All of the larger Papal States save the Vatican itself were occupied and absorbed by Italy by 1870. The resulting Roman Question was resolved with the rise of the modern state under the 1929 Lateran treaties between Italy and the Holy See.) "Legitimate states that govern effectively and dynamic industrial economies are widely regarded today as the defining characteristics of a modern nation-state." Nation states
Basic Law for the Federal Republic of Germany Government itself and by the Federal Constitutional Court. Initially, the 1949 constitution of the German Democratic Republic adopted a mirror image version of this claim; in being framed in anticipation of a future all-German constitution on its own political terms; but all references to a wider national German nation were removed in constitutional amendments in 1968 and 1974, and from that date the GDR maintained that from 1949 there had existed two entirely separate sovereign German states. The Federal Republic's Cold-war Allies supported its claims in part, as they acknowledged the Federal Republic as the sole legitimate democratically organised state