There are three good solutions: 1. Maintain a 6 months (or whatever time is necessary to restart production) stockpile 2. Have a highly credible policy that,

There are three good solutions: 1. Maintain a 6 months (or whatever time is necessary to restart production) stockpile 2. Have a highly credible policy that, if any foreign country actively opposes free trade of anything important, an ICBM loaded with a nuclear warhead is launched on their main government building or biggest city 3. Change things so that there is no advantage to producing abroad, if possible (e.g. allow unlimited immigration, remove taxation, remove minimum wages, remove regulations, etc.)