Who knows?
It is hard to imagine, however, that in a real crash there would be totally safe havens.
Perhaps precious metals, but this from history worries me:
I always thought Obama would do something similar in a heart beat. Hell, he would have even enjoyed it.
Would Trump? Ah...now that's a question. My suspicion is yes, if pushed far enough and he felt he had no other options in an attempt to stop the whole ship from going under the waves.
FDR had to change the price of USD to gold, and ban public gold holdings - because the world at the time was on a gold standard. FDR conducted outright thievery from the American public.
Now the world is on a 100% fiat, central-bank printed money standard, so for now anyway, its immediate role on the USD and other currencies is greatly reduced.
Sadly, no one sees the connection between gold and limited-government and freedom any longer. A government and central bank that can create unlimited debt in a printed currency with manipulated interest rates can pursue any repression and social-engineering scheme it wants.