Following this line of reasoning, they should drive us out and occupy the land.
Before you get out your flamethrower, I hasten to say I'm not advcating this point of view; I'm just saying it's as plausible as yours.
I think Mark Earley's got it about right: acts of compassion at the personal and Church level; even-handed law enforcement at the government level. He argues his point well--- just what I'd expect from Prison Fellowship--- in a principled, lawful, and Christian manner.
We Christians are the people of His covenant now.
Regardless of what one wants to claim about abortion, the U.S. is the most moral nation on the planet, with more practicing Christians than anywhere (perhaps not as a % of population, but in sheer numbers). This is a glass half full vs. half empty argument.
If there was no such thing as "citizenship," Paul would NEVER have made such a big deal out of his civil rights as a Roman citizen. He would have had to say, "Well, I'm just another alien, so who cares. Kill me." But he appealed directly to Caesar on the basis of CITIZENSHIP LAW.
By their very nature in coming here illegally, the Mexicans have no more part in the "covenant" than anyone else. God doesn't like lawbreakers, and said so in Romans, repeatedly. Oh, and don't forget, they were the ORIGINAL child killers (Aztecs) in their previous incarnation.