Trump cares. About one thing and one thing only. Trump cares about Trump. He is the ultimate narcissist. And a lying sack of sh!t. In that order.

Trump doesn't care about the wall. Trump's narcissistic self cares about his inflated ego. Therefore, Trump cares about fulfilling his campaign promise to the deplorables and other idiots who voted for him. And he did say Mexico would pay for it, and not through a re-negotiated trade deal. He said it in black and white printed campaign material and in digital voice recordings. He's on the record that Mexico would pay for the wall. It's that simple. Trump can have whatever wall Mexico will build for him. Why waste US tax dollars on a Trump campaign promise? That even sounds illegal, using tax dollars for campaign purposes.

A wall would likely be partially effective at stopping some illegal immigration, but that doesn't make it cost effective or an objectively good idea. There are other ways to deal with illegal immigration, especially since most illegals in the US are aliens who over-stayed their visas. Hence a wall will have zero effect whatever on this.

A wall would have zero effect on stopping illegal drugs from entering the US. Drugs come into the US through normal ports of entry in trucks and semis loaded with other legal goods. Drugs come into the US because they are illegal products that have a vast and large demand. A wall will have zero effect on this, so stop calling drugs a reason for this stupid as sh!t wall. This a good time to mention that making marijuana legal in several states has put a serious dent in the import of pot from Mexico. Fvcking wow! Who'da' thunk? Make all drugs legal, and the import of same from Mexico will stop. It's been known for at least 2 decades that the War on Drugs has been both a fiscal and use disaster costing over 100 billion dollar a year. It would be both cheaper and more effective to spend some of that money on increased drug education and drug treatment. And then send the hopeless druggies, along with Hank, Evo, and Slo Dunce to some deserted island somewhere that's anywhere but here.

Other reasons why the wall would be a colossal waste of money is that, although the Cascade Mountains in fact don't run from Maine to Washington, the desert doesn't run from the Pacific in CA to the Carribean in Texas. In some places there are mountain ranges, rocky and steep as hell that are not conducive, let alone remotely cost effective to build a wall of either concrete or steel or even a simple barb wire fence, which is why it remains, and most likely will remain unwalled and unfenced. If you've ever heard of places where you can't get there from here, this is one of them. And for a long stretch of the border runs the Rio Grande River. Most of the year there is little or no water in it, but some times there is a lot. Where ya' wall supporters gonna' put your GD wall? There isn't even a fence. Why? Because the river would wash it away most every year during that high water period. Additionally there are people who live along that stretch on both sides of the river. They and their forebearers have lived there for hundreds of years. They think Mexico and Texas are the same place, because in that area they are the same. The governments of the US and Mexico think there is an imaginary line down the river separating the land into two different countries. But you can't see it, and the land on both sides looks exactly the same. And in the area of Big Bend National Park Mexicans living south of the river cross it daily into the Park to sell crafts to tourists and park visitors. (Officially they cannot sell crafts because they are not official Park Concessionaires, so they leave a can for "donations". It's on the honor system and seems to work out OK.) The National Park Service knows it, Immigration knows it, and Border Patrol knows it. Yet there is no port of entry border crossing. People just come and go, going about their business. Is a wall necessary for national security here and to keep "Americans" safe from violence and terrorists and illegal drugs? How would a wall improve anything in this region? And be anything besides a colossal waste of money, regardless of who pays for it?

Wall supporters are incapable of analysis and don't know their heads from their assholes. Possibly because there is no difference.