Nonsense....But let's see if you know what you are talking about....Explain why you think what I bolded....
I live about 40 miles from the border and have for most of my life both here in New Mexico and in San Diego California.
I have spent a LOT of time on this border from the Pacific Ocean in Tijuana to El Centro and Yuma in Cali to Lukeville and Nogales in Arizona to Aqua Prieta, Palomas to Ciudad Juarez/El Paso TX in NM/Texas.
I have done backcountry hiking and offroading on the U.S./ Mexico border in the wilds of Big Bend and am intimately familiar with the complex international border situation in the agricultural corridor east and south of Big Bend on down to Brownsville and Matamoros.
I can tell you that much of the international border is wild.
EXTREMELY wild....and (for the most part inaccessible.
Hundreds and hundreds of miles between things.
No roads.
No infrastructure.
No people.
No way to "monitor" any type of actual physical barrier that isn't already being employed and have been already for years.
Tethwred Aerostat blimps during the Reagan years.
Electronic sensors placed in the desert that "trip" when human traffic passes by them.
Actual physical barriers (walls) that are either completely destroyed and/or tunneled under, broken, through, or scaled on a regular basis.....because there just isn't enough manpower to keep an eye on every square foot of a 2,000 mile "barrier" 24 hours a day, 365 days a year.
And I haven't even mentioned the NATURAL physical barriers.
Hundreds and hundreds of miles of deadly, inhospitable desert in all directions that must be navigated both before they even get to the border and then after they have jumped it.
Of course punctuated here and there along this border there a few HUGE bi-national metropolises.
They are a whole DIFFERENT story....with literally tens of thousands of people crossing back and forth every day in vehicles and on foot for work and other business.
Usually monitored by an anemic and inadequate, overworked Border Patrol Station.
No, it's just NOT do-able.
Not even for a trillion dollars!
And it wouldn't work anyway.
Nothing has.
I haven't even mentioned the fact that about 1200 miles of this border consists of a shifting and constantly changing riverbed.
Better add another trillion dollars to the cost of constructing anything like a wall down the middle of a river.....then get ready to do it again after the next flood when the center of the river moves and the actual international boundary changes place!
And finally, I know the old question, "well how do OTHER countries secure THEIR own enormous, wild borders?
China?
Russia?
Apples and oranges.
Those borders aren't anything like this one.