Yeah this isn't a viable way to formulate public policy. It isn't new either, happened with the travel ban early on. Soft power, and even the viability of a country, depends on certain long-term guarantees, guarantees that the current administration has blown away completely.
I'm pessimistic that even if a change in administration occurs early next year (and that is a major if), there would be anything any administration can do before the next Donald Trump takes office 4 or 8 years from now. I'm betting that the next "Trump" will be far smarter and won't make this one's mistakes. And if the Republic falls, no place on Earth will be safe.
That's not a reason to lie down and die. It's a reason to fight back with the frenzy of despair. I hope a quarter million dead by December will be enough. Enough for folks to remember that elections have consequences.