The objective of the author in this article is to demonstrate that Trump's idea of building a wall in the southern border of the States is not necessary at all. He thinks, and prove with stats, that America is not in a national security emergency involving terrorists. In fact, he claims, 2018 saw one of the lowest yearly numbers of jihadist terrorism cases in the United States. Also, he says that it is known an proved that the majority of terrorists don't enter the United States at the southern border because they are already in the country. Today, in America, terrorism is almost a homegrown phenomenon driven by jihadist material on the Internet, which happens to have no border limits at all.
On the other hand, some weak points of the author's argument could be when he claims that the number of terrorism cases nowadays says something about the scale of the treat. Also, he says that ISIS recruitment has slowed to a "trickle" and those are facts he can't really be sure of, because if they are actually preparing an attack or recruiting people nobody would tell. As he said before, many of the terrorists were convinced to be part of ISIS without anyone telling or even imagine what was going on. It would not be an evident process and that is the key of it all, the most difficult part; this could be the less convincing argument.
