Your question is more a philosophical one than an economic one, but indeed essentially the old principle of trade policy is based on the capacity of markets to adapt to changes. Of course in some cases, it could warrant government intervention if there are externalities that the government would like to take into account. But overall, the trade policy changes are based on the assumption that markets will readjust to the new environment.
On October 6th, 2016. See this statement in context.