The German philosopher Jürgen Habermas long ago recognized that capitalism has the tendency to develop a 'legitimacy deficit'-- a situation in which citizens, independently of their political beliefs or ideology, lose confidence in the right of political and administrative authorities to act as they do.
[...] a federation replaces sovereignty forfeited at the national or state level with sovereignty at the unitary, federal level, centralizing power within an alliance of states is, by definition, illegitimate, for there is no body politic that can legitimize it.
German unification began with a customs union known as the Zollverein, an 1833 agreement between the various territories promoted as a first step towards freer trade and much needed economic integration.