Answer: to protect the economic freedom of all of its citizens
Step-by-step explanation:
The above quote by Adam Smith was him criticizing the common practice in those days of nations trying to control the spending habits of their citizens by passing restrictive laws and limiting the importation and production of certain goods and services.
It would therefore support the U.S. policy of protecting the economic freedom of her citizens such that they may trade whatever it is that they want - so long as it is legal - without restrictions by the government.