[nightcracker]

> You can't take your tent, set it up somewhere in another country and declare you live there without some fiscal authorities coming for you at some point.

The only 'requirement' is that the government (may) want to see you can provide for yourself in the form of capital, a job, a retirement pension, etc. This is because most countries in the EU have a social safety net, and some have a very strong one. Without this rule the countries with the most generous social security would see mass immigration from rent seekers with no recourse.

The USA doesn't need this rule because it lacks the strong social security.

[alibarber]

I think it doesn't need the rule more because it's a single federal republic and its citizens are citizens of the entire nation not just a single state.

Whilst it's great to make generic EU vs. US statements the EU(/EEA) is still ~30 different sovereign nations with their own citizenships.