In defending this course of action, Trump claimed that “if they don’t buy [weapons] from us, they’re going to buy it from Russia or they’re going to buy it from China or they’re going to buy it from other countries.”
While it’s true that Russia and China are indeed major exporters of armaments, the claim that U.S. weapons can easily be replaced by other suppliers is not – at least not in the short term.
First, once a country is “locked in” to a specific kind of weapons system, such as planes, tanks or naval vessels, the cost to switch to a different supplier can be huge. Military personnel must be retrained on new equipment, spare parts need to be replaced, and operational changes may be necessary.