[inquest]

[Why would they need to be replaced immediately? It's not like they'd be going anywhere in a hurry.]

If we want to control the borders, they should be going fast.

I'm not following you here. If we get control of the borders, the illegals who are already in the country won't automatically disappear. They'll still continue working at the jobs they're currently working at, until replacement guest workers arrive. What am I missing in this?

[speekinout]

What you're missing is that as long as we continue to allow illegals to work here, they have an incentive to keep coming. And all the fences in the world won't stop them. They can get here by boat, or even by coming in as tourists and just not going back.

If we allow illegals to work here, how would we know the difference between the ones who got here yesterday and the ones who have been here for years?
Until we insist that everyone who works here must have a legal status, then we are inviting more illegals.