In his public letter responding to Trump, López Obrador said Mexico is already doing what it can to stop the migration, and added that “social problems are not solved with duties or coercive measures.”

He said he is developing plans with Central America and told Trump: “Please, remember that I do not lack valor, that I am not a coward nor timorous but rather act according to principles.”

Citing the United States’ history as a nation of immigrants, López Obrador also told Trump: “The Statue of Liberty is not an empty symbol.”