Generally a government can give away things to other countries. Now, for weapons they have imported, the import agreement may require that the country of manufacture approve of any re-export of the weapons. This happened recently with Spain who wanted to send Ukraine some weapons they had imported from Switzerland, but the Swiss blocked this because the terms of their arms agreement is that Spain can’t re-export the weapons without Swiss approval.
So, if the Dutch are re-exporting American weapons, it’s likely because the US doesn’t have a problem with where the weapons are going.
Latest Answers