[nico_h]

If it’s sourced from abroad it has to be shipped (blockades anyone ?)

If your usual trading partner is inaccessible for reason X , what are the odds your alternate trading partner is also affected by reason X? Are there geopolitical or national political reasons that partner B might become unavailable or unpalatable at the same time?

[energy123]

Maybe, but it has to be balanced against the economic damage of autarkic policies which sabotages national security in its own way. There's no substitute for a case by case analysis.