I agree that any illegal alien who is picked up by police for a crime should be deported. But this thread was about deporting ALL illegal aliens, now. Does everyone who talks to police have to prove their citizenship? What if you don't have a passport/birth certificate or Drivers License on you? Off to jail you go?
No, there are plenty of laws on the books that will facilitate deportation without violating the constitution.
Catch an illegal, find out where they live, and execute a search warrant on the residence. You'll likely find more illegals living there.
Plus, once you start actually enforcing the law - especially by going after employers of illegal aliens, you will make it less desireable to work here.
All you really need to do is start chipping away at what keeps them here - work, benefits, other illegal family members- and they'll start to leave on their own.
If you want to really get them to leave on their own, pass a law that anyone caught in the country illegal will be subject to asset forfeiture, since their assets would likely have been gained as a result of the intial crime. (like they go after the results of white collar crime). USe the money to pay for the reward system and enforcement.
The problem can be solved pretty easily if there's actually a will to do it with politicians. However, most of them are sold out to special interests, so instead of solving the problem they wring their hands and cite horror stories of how we just can't afford to do it, from either a dollar basis or a "human cost" basis.
Either way, it's just pathetic excuse making, and it's costing billions of dollars and many lives by doing nothing.
All illegals have committed a crime. That's why we call them illegals.