Trump is spewing hot air on this one. As a businessman I'm not so sure he actually wants the border closed as he says he does. I believe he wants the illegals to stop pouring into our country but Mexico = $$. Consider this:
** "Mexico was the United States’ 2nd largest goods export market in 2013.
U.S. goods exports to Mexico in 2013 were $226.2 billion, up 4.7% ($10.2 billion) from 2012, and up 132% from 2003. It is up 444% since 1993 (Pre-NAFTA). U.S. exports to Mexico accounted for 14.3% of overall U.S. exports in 2013.
The top export categories (2-digit HS) in 2013 were: Machinery ($38.5 billion), Electrical Machinery ($36.7 billion), Mineral Fuel and Oil ($23.0 billion), Vehicles ($21.6 billion), and Plastic ($15.3 billion).
U.S. exports of agricultural products to Mexico totaled $18.1 billion in 2013, the 3rd largest U.S. Ag export market. Leading categories include: corn ($1.8 billion), soybeans ($1.5 billion), dairy products ($1.4 billion), pork and pork products ($1.2 billion), and poultry meat (excluding eggs) ($1.2 billion)."
Mexico was the United States 3rd largest supplier of goods imports in 2013...
***https://ustr.gov/countries-regions/americas/mexico