It's not that simple. We have to have a comprehensive plan, and we don't. If you just increase enforcement, that will do nothing. If you just change the rules (asylum, dreamers...whatever), that will not do much. We need to change our system to allow for migrant workers, to address dreamers, to penalize employers who don't use some sort of verification system (e.g. my former employer used the one that already is in place to verify eligibility for employment -it's my understanding Reps in particular hate this), asylum, and various other measures all at once. Once we address these various issues, then the only ones crossing the desert are going to be the bad ones...and it will be much easier to catch them if that flow is a trickle instead of a torrent.

That doesn't address people who overstay their visas, which actually is a bigger problem than people hoofing it across the desert. Employment verification would address most of that (i.e. can't work, then it's hard to live here).