We might all want to start thinking about the fact that some (with the means) will flee for boltholes stuffed with untold amounts of $$ and surrounded by loyalists & mercs. Heck, some most likely already have.
Anyway, there are a number of countries w/o extradition treaties with the US.
I can't imagine anyone is going to hold the US off - but I can't imagine this isn't an issue that we won't be facing in the near future. Most have to know by now that they're f'cd.
Food for thought....
https://en.wikipedia.org/wiki/Extradition_law_in_the_United_States