[quote=@mdk]
When you do the math on the financial impact of illegal immigration, building a wall is about 90% cheaper (assuming a 100% elimination, which is a faulty assumption, but just for the sake of argument). It would save us money; and in terms of feasibility, large portions are already built (the wall was already approved years ago -- Clinton actually voted in favor). But anyway "physically (im)possible" just sounds like a challenge. I do physically impossible shit every day. Dream big! 
[/quote]

I feel like this bit highlights all the practical problems with building a wall, and why it isn't a worthwhile investment, and why it is mostly a political red herring used to keep us from focusing on our real problems. 

1: That 100% effectiveness is unlikely and shouldn't taken into calculation. 50% elimination would be wildly impressive.

2: That we've already got walls in the sensible places, and what we are mostly discussing now is the utility of building walls across the remote deserts and mountains that make up so much of the border.

3: That it would be a continuous cost to upkeep a massive piece of infrastructure that more or less doesn't do anything. This means it would probably be abandoned in portions as both parties look to reapportion that money to active projects, so that I would expect the Trump portions of the wall to be mostly abandoned and let go into ruin since they are impractical.

I personally don't have a problem with them building the wall. I'd rather Trump focus on it, actually. Sure, it's a waste of money, and there is probably some dark and dirty corruption behind the plan, but corrupt wastes of money is something we can swallow and forget. Get the dumb thing out of the way so we can get to forgetting about it sooner, and hope that Republicans don't start pushing something equally "useful" like building a really really really tall tower on the Canada border so we can see to the artic.