> But we've now done the experiment in a big way and the results seem overwhelmingly negative to me, to the point where they present a credible existential threat to civilization, on a par with climate change.
A lot of these issues seem largely peculiar to the US. Trumpism, birtherism, Pizzagate, "Stop the steal", QAnon, etc – all movements originating in the US, focused on US-specific political issues, and with most of their followers in the US. Other first world countries don't seem to have this issue to anywhere near the same extent.
And that's why I don't think it is "a credible existential threat to civilization, on a par with climate change". A credible existential threat to the future existence of the United States maybe, but the US != civilisation. The US could all magically disappear tomorrow, and human civilisation would survive. It would be a setback, no doubt, because the US makes an important contribution to the global economy, but nothing the world couldn't recover from.
And, the realistic worst case scenario isn't the US magically disappearing. The realistic worst case scenario is that Americans get worse and worse at co-existing with each other to the point that the idea of breaking up the US becomes mainstream, and then it maybe actually happens. If that came to pass, it would be the end of America as we've known it, but it wouldn't be the end of human civilisation.
> Other first world countries don't seem to have this issue to anywhere near the same extent.
The kinds of things you listed happen all the time in marginal, developing, or failing democracies. There are a lot of people who believe that the US shares many of its attributes with ailing democracies, so this should not be too surprising.
A lot of these issues seem largely peculiar to the US. Trumpism, birtherism, Pizzagate, "Stop the steal", QAnon, etc – all movements originating in the US, focused on US-specific political issues, and with most of their followers in the US. Other first world countries don't seem to have this issue to anywhere near the same extent.
And that's why I don't think it is "a credible existential threat to civilization, on a par with climate change". A credible existential threat to the future existence of the United States maybe, but the US != civilisation. The US could all magically disappear tomorrow, and human civilisation would survive. It would be a setback, no doubt, because the US makes an important contribution to the global economy, but nothing the world couldn't recover from.
And, the realistic worst case scenario isn't the US magically disappearing. The realistic worst case scenario is that Americans get worse and worse at co-existing with each other to the point that the idea of breaking up the US becomes mainstream, and then it maybe actually happens. If that came to pass, it would be the end of America as we've known it, but it wouldn't be the end of human civilisation.