If illegals can't simply walk across to assemble in an nearby predetermined area on US soil for distribution further into the US, or vehicles driven across loaded with drugs in remote areas for the same reasons of distribution, then, would all such trafficking have to be done by air or sea or secured border crossings? Hell, no excuse in my book of common sense.
How many interstates have we built in the US that run completely from the east to west coasts? The southern border is only 2000 mi long....a serious wall/fence combination with outposts could be bid out to several companies and all construction finished in less than 6 months.
Go figure. Just cut foreign aid to other countries (and other give away programs long enough to cover the costs and then let INS and the military handle the patrols.
6-8 billion is the cost, sooner or later it needs to happen.