There's no real need for extreme fences and all the other distractions. Its amazing how well the politicians play people and get them to believe what every other country in the world does is impossible in ours.
Simply ENFORCE the immigration laws. Not even against illegals primarily, but against businesses. Go back to extreme fines at best, forfeited assets and jail sentences and at worst for businesses that hire illegal workers. No other bullshit is needed. Cheaters of the system actually need to always have more to lose by getting caught cheating, than they gain by getting away with it.
Of course some will still cheat, but the overwhelming majority of businesses wouldn't go near illegal workers if getting caught meant serious shit hitting the fan. On the flipside, no govt freebies for illegals that are only for citizens. Legalize MJ and dry up a big part of the southern drug trade as well. Once the economic lures are gone, there's no need for any fences. Only a.manageable amount of people will bother trying.
As it is, our own govt basically hangs out "come up to the US!" signs all over Central America and then does a wink and a nod with corrupt employers.
Its funny how Dims and the usual class-envy suckers normally want to stick it to business any way they can, but they've swallowed so much horseshit from their puppetmasters who want their hordes of slaves brought in, they actually hand corrupt businesses a perfect out of skirting labor laws and shafting US workers royally.
Economic illiterates carry water for cheating businesses whining about "labor shortages" (translation: you can't be replaced at a minute's notice by a trained monkey... you're actually worth more...oh noes!) and "Jobs Americans won't do!" (Translation: entire industries that used to pay citizens enough to live well now turned into shit jobs ONLY illegals will do for nothing... cheered on by morons slitting their own throats.)
So of course.. every nation on earth has high fences around it rather than immigrarion laws that protect their own citizens over any refuse that just wanders in.