Expanding from a comment thread: https://www.lesswrong.com/posts/3jYwvwrNXyD3koHTM/open-and-welcome-thread-june-2020?commentId=FcZwHEWEt6EAP54qq
Growing up, I had a neighbor who'd escaped the Cultural Revolution as a child, going from very wealthy in China (she had bound feet, and had literally never seen food being cooked) to working- and then middle-class in the US. I have a number of friends with relatives who escaped or survived (or didn't) the Nazi Holocaust. In both of these cases, there were many months where someone could get out pretty easily (but at significant cost), but it wasn't clearly necessary. And then many weeks where the rich could get out (at a very high cost), and then it was too late. The US Civil War took 4 months from first declaration of secession to the shooting war starting at Fort Sumter. Travel was much harder back then, so I'm not sure how possible escape was was for most.
As things get ... weirder in the US, politically and economically, there is a (very low IMO) chance that things will collapse badly enough that it's worth significant disruption (leaving friends and family, possibly abandoning hard-to-move assets, certainly incurring expenses) to move out.
I expect that my perception of the chance over time, conditional on it actually happening, to be roughly logistic in shape, and with some intersection on a graph (whose shape I'm unsure of) of "cost/difficulty to get out". And complicated by contagion - it's not clear the US can fully collapse without taking with it most places I would want to go.
So: what are YOUR triggers and preparations for escaping if Very Bad things happen in the US?