a continent united through trade, (mostly) shared currency, open borders, and a union that governs over member countries each having their own laws.

Now compare it to the US, united through trade, open borders, shared currency, and a federal government that governs member states that each have their own laws.

obviously there are major diffences between the two but for the sake of comparison in the "who put more effort into something" debate comparing US and Europe on the grounds of "single country vs many countries" is rather silly