Sorry, but I don’t really think a fence is the answer.
http://www.huffingtonpost.com/2014/07/29/border-fence-knocked-down_n_5631316.html
Everyone lauds the fence in Israel. I do too. But that fence is relatively short and manned 24/7 by military.
We can’t do it now...or won’t.
Cut off the benefits. No free schooling, no access to free medical, no access to government benefits. Fine the employers that hire these folks in a huge way. (=no jobs). NO...NO anchor babies.
As long as there are ladders and shovels to dig tunnels a fence is an illusionary fix.
Cut off the benefits and use the savings to built a fence in the places that need it most.
Naturally, a serious double fence would be heavily manned, by today’s current BP. At the present, they must “defend in depth” from the border back 40 miles. 2.000 miles X 40 miles = 80,000 square miles to play hide and seek with coyotes, aliens and drug smugglers.
Question, do you bother to lock your doors and windows when you go on vacation? After all, a cat burglar could pick your locks and disarm your security system. So why bother?
Using your same “logic” the White House and every military base etc should get rid of their fences, because fences are not 100.00% effective at stopping every type of incursion.