Prism

The politics of the US are stuck in how they were when Britain founded colonies on American soil anyway.
Pretty much every major shift European politics have gone though since then hasn't applied to the USA.

I wouldn't say that's much of anything relevant since so many European countries went through so many changes to get to their liberal democracies. Hell, take Germany as an example. Loose collection of largely independent states, unified under an authoritarian ruler, a democracy, a totalitarian state, two separate ideologically countries (one liberal democracy, one "communist") finally unified as one liberal democracy. Britain's also been a constitutional monarchy for a good while.

The political parties' ideologies have changed a considerable amount as well.

[MENTION=2088]Flonne[/MENTION]; Europe is in heaps of trouble for completely different reasons.