Page 6 The Trump Immigration Wall
First off Mexico is not a third world country (And for that matter neither is Canada). There are very few people from other countries coming in through the Mexican border. I understand the frustration that people are illegally coming in and taking resources from our government that could be used to better the legal citizens, but if you go read the research the majority of the illegal citizens actually pay taxes through automatic withholding at work, but can never see the benefit of those taxes (Beyond general road upkeep and stuff).
Regardless of all that previous stuff, building a wall will not solve any of the issues we have with illegal immigration. It will be just like cyber security. Every time you upgrade security the 'bad guys' just get smarter. Whoever you are trying to keep out is infinitely more adaptable than we are. No matter how many cameras we add or how good our 'tunnel sensing' technology is, no matter how many guards we staff it with there will still be illegals coming to America. They can come by sea (Which is more dangerous, but if you build a wall they will find a way), they can come through Canada (If you are worried about terrorists and such that aren't necessarily poor mexicans), and they can just keep coming through the 'wall' because no wall is perfect. This is a poorly planned idea that doesn't need to be funded. It won't accomplish its goal and it is only taking resources from the already underfunded schols you previously cited. All the money for this project is cut from other government responsibilities (Funding science, education, housing and urban development, park upkeep, etc). There is no 'new' money being injected into the economy to fund this, it is just re-appropriated from other sources. Instead of $1.6 billion going to the wall we could fund the school lunch program or the national parks program or science. $1.6 billion won't get much of a wall (As the article states), but it would make a big difference if spend elsewhere.