I don't know much about the example you mention, but it seems to me as you describe it that this is a case where there should be a rule—I don't know; there must be one—allowing for purchases in case of emergency, which is a totally distinct concern from national security. If national security was invoked, it's probably because the government started to see it as an easy way out, and it shouldn't.
On May 2nd, 2017. See this statement in context.