Damn it, fuck this shit. You're fearing yourselves into Californian unsustainability.
Step 1: Amnesty to anybody who makes it over by land. This includes everyone who's already here. Get them out of the dark so you can document them and learn about who they are, the sooner you can force them to pay taxes at gunpoint.
Step 2: Purchase miles of land by border
Step 2.5: Lay multi-staged landmines in purchased land, antipersonnel through both trip detonated and command-detonated in border areas. Invest in anti-tunnel technology, or whatever the Egyptians plan to use by 2014 ( they really reaaaaly don't like Hamas and their smuggling to Gaza on fear of growing influence in the Muslim Brotherhood).
Step 3: Link command-detonated landmines to a website where users who log in from a united states location (no proxies) can sign up a user name based on their social insurance number and some tax information so that these volunteers can command-detonate fields covered by surveillance equipment, killing anyone who tries to make it across. Ensure that website is ad-supported, and that those found guilty of activating landmines with no visible presence of attempted border hoppers, or any other indication will be liable for the cost of replacement of the landmines ensuring fraud doesn't take place.
Step 4: Place phones and aid stations on american side of border for successful illegal immigrants. Include fast-track green card forms, first aid, food, and water. Entering the shack will alert federal authorities, who will welcome illegal immigrant with a hug, a Martguerita, a USA baseball cap, and anything that's required to integrate the individual into american society....
For if someone really wants to be a US citizen so hard that he's willing to risk the worst kind of life and limb, then I guarantee you that as soon as he or she learns the language, the citizens those types will make will be a vast improvement over some of the nuts on both side of the political divide willing to shout down their gov while sucking off its teat.
That and it's probably more humane that what they already go through. It would probably cost a lot less to implement and keep the crazy redneck types at bay: "I got one!"
Also: If anyone complains about the minefield: Catapult them into the minefield.
2nd clarification: This is a joke, brought on by reading too much PJ O Rourke and John Ringo. In no way do I really condone using landmines on civilian targets, as not only is it against the Ottawa Treaty of which my nation is a signatory, but considering the command-detonated mines, government sanctioned murder is not acceptable in areas which are not considered theaters of war, and then only against those which are deemed to be reasonable targets by someone with no less than executive power.