“Yeah. Yeah. If China should deprive our fighting men and women of their berets, what will we do? Answer: produce them in the US! ...or Pakistan.”
It involves far more than berets. That was just a fairly amusing example. But production can’t be instantly moved to another location, particularly for more complex items used by the military.
I know I read of two examples of foreign suppliers refusing to resupply the Brits because of their opposition to the war in Iraq. Once was a Swiss company that supplied grenades, and there was another perhaps French company that refused to supply them with some other items.
Allowing any basic production for our military to go overseas is one of the dumber moves that has been made.