> You seem to be implying that the US is the only place with diversity and that that somehow is an excuse for the US not having social security measures common in other countries.

100% nope. Where did you get that? I'm in favor of social safety nets. This entire thread is about how easy it is to enact things like "No petrol based cars by 2025".

That's easy to do when you've got 4 million people spread over a small amount of space who come from similar backgrounds. That's harder to do with 300 million people spread over a large amount of space who come from different backgrounds. A small club is much easier to manage than a large club, I don't see what's so hard to comprehend about this.

> But are these requirements really that fundamentally different?

Yes... insofar as you get groups of people who stop thinking that it's their responsibility to cover the costs of the other group. Should people in North Dakota pay for national flood insurance of people who live in southern flood prone regions, even though it's basically guaranteed to flood there eventually? Should people in New Hampshire pay to replace homes lost in california forest fires even though it's basically guaranteed to burn in certain places? What you think is "right" on this issue doesn't matter. What matters is that people in those regions have differing opinions on the matter, and it is objectively harder to get them all to agree than a small country where people tend to have the same problems concentrated in a small place they all share.

Throw in the really controversial stuff like social issues, and the left and the right constantly trying to push their vision of it on the whole country at once, and you can see why maintaining a continent sized empire is more logistically challenging that keeping a small country together.