If he uses National Guard he can do it on our side of the border. If he uses regulars he will have to invade into Mexico on the other side of the border. Establish a DMZ, kill anyone who crosses unauthorized. Tell Mexico, the democrats and the rest of the world to go to hell. But, really now, that won't happen. Mexicos economy depends on all that money being sent back across the border. All the drugs being brought across. Payoffs? Yeah, lots of crooked shit going on our side of the border too. Its all theater. Dems want new dems. Republicans want to keep the cash flowing. Dope is like oil. if its bad for business its not going to happen.
I had a DEA agent tell me about 20 years ago that if the border was shut down, and all remittences to banks in Mexico were stopped, The economy of Mexico would collapse in a week and the country would be in total chaos. He said he worked on the the "internal Study" that sleuthed it all out.
Border won't be shut down. People will still come here illegally and the money will keep flowing. Flowing until everything collapses. It's all over but he crying'. Best prepare for whats next. Move out of the cities, get some acreage and learn how to grow your own food. Make friends with like minded people. Stockpile weapons, ammo and food and keep your mouth shut and wait. Plan plan plan. PACE planning will be your friend when it all goes down.