Some of the more substantive of the points brought up in the discussion in the comments recently is this issue of legality. It’s an important issue so I’m going to address it up here and try to keep the conversation going.
The first thing to keep in mind is the difference between morality and legality. I have a hunch that those who posted probably have a love for law and order that only extends so far, and maybe wouldn’t include issues with a President who has decided to ignore 750 someodd laws over the past six years. There is an imperfect overlap between what is moral and what is legal. Take the civil disobedience during the first civil rights movement: illegal acts, but not immoral ones, although there were certainly those who disagreed with their morality at the time.
But beyond that, there’s a simple but important question that has to be considered in thinking about this issue…

What would you do?
A thought experiment: put yourself in the shoes of someone who is deciding whether to stay in their country or to come here. The drive to provide for one’s family is maybe the single most powerful motivator of human behavior. If all you had to do to provide five or tenfold as much for your family was cross a border – you’re not hurting anyone, just crossing a border – would you do it? I certainly would. An illegal act, but not an immoral one.
Another substantive critique is this issue of impacts: perceived costs, population growth and so on. As for the schooling of new immigrants’ children, like all children they are absolutely worthwhile investments. We’re the richest state in the richest country on earth. We can afford it. When did conservativism lose its ability to see beyond this month’s tax bill? This isn’t that difficult: If you invest in kids, ten or twenty years later they are productive members of society regardless of the color of their skin. If you don’t invest in them, bad things happen and we all end up paying much more.
Population growth and assimliation issues are solveable, too. One of the benefits of an open, secure border would be that it would be as easy to leave as it is to come in, restoring the seasonality of at least some of the workers who have come here. As for our crowded highways and cities: this is a land-use issue, not an immigraiton one. The vast majority of what we’ve built in this state since World War II is suburban sprawl, so of course we have lousy traffic. There are known solutions to this problem (such as new urbanism) that don’t involve putting the state at odds with people’s desires to do right by their families.
But back to this issue of understanding human reality: this seems to be an issue with a lot of what passes for neoconservative policy making. Iraq comes to mind. It’s not that big of a stretch for most folks to imagine what they’d do if a colonialization-minded superpower invaded their country and tried to take over. If it happened here, I’m quite sure I would be a grunt in the first Dolores Park division of the Free San Francisco Liberation Front or somesuch.
It almost makes me wonder if chickenhawkdom lies at the base of these decisions. Maybe the leaders who proposed HR4437 and the Iraq invasion are not the sort of people who would do the hard things. Maybe they wouldn’t cross a border to provide for their familes, and maybe they wouldn’t defend themselves against a military occupation. I doubt it; more likely it’s just garden variety xenophobia combined with entirely understandable feelings of economic insecurity, and Iraq is just faulty geopolitical calculus and the Vice President and Secretary of Defense drinking their own kool-aid.
I don’t know much about the underlying psychology that creates obstacles to understanding where people are coming from though. Maybe there is a connection?