The great minds that - after WWII - built the new Europe had in mind that there should never be war again, which is best realized when former enemies become friends and closer bonds are established at multiple levels: politically, economically, culturally (unions, trading exchanges, visits/open borders/teaching common European values in schools).

There is a strong political and cultural foundation in geographic Europe for the political EU: some exemplary giants/EU co-architects:

Jean Monnet/Robert Schuman

European Coal and Steel Community (ECSC) Schuman Declaration (1950) [It is only right that the R. Schuman Roundabout https://en.wikipedia.org/wiki/Robert_Schuman_Roundabout Rue houses the European quarter in Brussels.]

Konrad Adenauer

Promoted reconciliation with France pro-European

Alcide De Gasperi

Integrated Italy into Western Europe Advocated supranational institutions

Paul-Henri Spaak

institutional designer, key role in the Treaties of Rome (1957) helped design the European Economic Community (EEC) Advocated supranational institutions

Walter Hallstein

1st President, European Commission. Built EC into powerful, independent institution Championed the supremacy of European law

Altiero Spinelli

Wrote the Ventotene Manifesto (while imprisoned by Fascists) Advocated a federal Europe

Winston Churchill

A paradoxical but crucial figure: called for a “United States of Europe” (1946 speech) Influenced Europe’s post-war direction despite UK distance

François Mitterrand

Drove Maastricht Treaty with Helmut Kohl Pushed for the € Symbolized Franco-German partnership

Helmut Kohl

Franco-German friendship exemplified by Mitterand-Kohl personal friendship "Architect of modern Europe" German reunification Key figure behind the EU and monetary union

It's ironic that the name "U.S.E." (United States of Europe) was first proposed by a Brit, alas a smart one, and I'm sure Sir Winston Churchill would have had the oratory abilities to convince his countrymen that his idea had merit, but he did not live to see it. The Federation of Europe or United States of Europe is the logical end-point of the joint vision of all these foundational leaders.