While I have never taken "the Trump wall" seriously and have great reservations, I am just finishing the book "Dreamland" by Sam Quinones on how Oxycontin opened the US to Mexican black tar heroin. Further he describes how easily the Mexican dealers spread throughout the US - easily. Far too easily.  Now that black tar shows up in every corner of even Alaska, I begin to wonder what the US can do to effectively slow and reduce this plague to our country?