The most common, and facially valid, argument against illegal immigrants and illegal immigration more generally is that they are here illegally and thus have no right to remain here. It is argued even by a certain libertarian-ish politician that we should continue to not only continue to view these immigrants as law-breakers, but we should also refuse to grant citizenship to their children who are born in this country. Indeed, he would like to see more taxpayer dollars funding border protection against immigrants (to my knowledge he has not proposed ways of allowing everyone into the country legally, by the way).
Here's the problem with the concept of illegal immigrants being law-breakers who must be dealt as such: at the time of their immigration, they're not subject to US law. So how can we possibly expect them to obey a law that they have had no say in, issued by a country that has no sovereignty over them.
I suppose you could say that once they're in the US, they're breaking the law. And I suppose you'd be correct. But, as a libertarian, I ask this: by what right, by whose sanction, are they obligated to follow a law that tells them they may not exist? Now I have no problem with denying benefits to them as long as they are illegal- I'm opposed to benefits in the first place, anyhow. And if they're not paying taxes, then I don't see how they'd be entitled to such benefits. But the bigger question to me is, and should be "why are they illegal in the first place? By what right do we tell people who are coming here for all the right reasons to come to a capitalist society that they may not exist? That coming here is simply not an option we will allow them? I suppose one could answer that it's our property and we get to say who can come onto it. But that ignores the rights of actual property owners to invite people onto their property. If you are concerned with traffic on public property, isn't the very concept of public property anathema to libertarianism in principle?
Moreover, wouldn't it be a hell of a lot easier to keep out the truly bad people if everyone had an opportunity to immigrate legally, and quickly? Why are the economics of limits on immigration any different from limits in other areas, like price controls, quotas, and subsidies?
And finally- if you haven't read the above-referenced piece by Rep. Paul, you should. As a libertarian, it is hard to read that piece and come away with the conclusion that Ron Paul is a libertarian at heart, not when he uses phrases like this:
How much longer can we maintain huge unassimilated subgroups within America, filled with millions of people who don’t speak English or participate fully in American life?
He also shows a remarkably poor knowledge of history, repeating this standard meme:
But the new Americans reaching our shores in the late 1800s and early 1900s were legal immigrants. In many cases they had no chance of returning home again. They maintained their various ethnic and cultural identities, but they also learned English and embraced their new nationality.
Of course the immigrants back then were legal immigrants more often- but immigration controls were far less restrictive. As far as I can tell, the first truly restrictive immigration cap was passed in 1927; in 1929, the US had nearly twice as many immigrants as the cap allowed (meaning there were plenty of illegals in the bunch); after that immigration went down for awhile, but you may recall that there was a bit of an economic crisis going on at the time. Also worth mentioning is the number of immigrants in the 1800s and 1900s who lacked any papers; how many of them wound up receiving bastardized names from immigration officials who couldn't figure out what they were saying (I know many people for whose ancestors this was the case).
In addition, the idea that the European immigrants of the 1800s and 1900s learned English more often than the current wave of immigrants is simply false, nothing more than a common misperception. As Tyler Cowen wrote in 2006:
Only about 2.5 percent of American residents speak Spanish but not English. The majority of residents of Spanish-speaking households speak English "very well." Only 7 percent of the children of Latino immigrants speak Spanish as a primary language, and virtually none of their children do.
The more I learn, the less and less libertarian Paul seems. I may yet vote for him, but if I do it will be with full awareness of his flaws, and only because the other candidates are even less appealing.