I agree that speaking of a global reserve currency is putting the cart before the horse, but I think the meaning was also clear. It was obvious that the 'foundational' currency within Bretton Woods was going to give its creator something that could be easily weaponized against other countries. And so they sought to make it 'impossible' to do that, but ultimately did so in a naive way - 'Here's all this power - please honor these rules that will punish you if you abuse it.'