Earlier quoted context omitted.
The US is very economically integrated with China. But it is not socially or politically integrated with China. Same could be said with US/Mexico, China/Taiwan, etc. The European Project sees social and political integration as ends themselves. It uses economic advantages as a way to convince voters to adopt policies that aren’t economically required.
> The US is very economically integrated with China. No, it's not. It is slightly economically integrated, and mostly in terms of physical goods. Are American IP laws applicable in China and the other way around? For example when licensing a Disney movie in the US, can I distribute it in China? Do you get warranty in China for any good sold in the US and vice versa? Do both countries use, by law, the same systems of…
In fact, the Canada has all three in common with the EU.
But the EU insists on open borders because they want social and political integration, not just economic integration.