A common complaint among many conservatives is that illegal immigration amounts to importing Democratic voters. It’s not the top line argument against illegal immigration. That would probably be the fact that it is illegal. But it’s certainly in the mix. On the right and the left there are lots of debates surrounding the whole “demography is destiny” argument. I’ve followed these arguments on and off for over twenty years now (my first boss in DC was Ben Wattenberg who was very bullish on increasing immigration). I think they can be overdone both on the right and the left. Neither a sense of doom (the right’s tendency) nor a sense of inevitable victory (the left’s tendency) are warranted. Predictions are hard, Yogi Berra rightly noted, particularly about the future.
Rather than get into all that, though, I think it’s an interesting counter-factual question to ask: What would the debate look like if the trends went in the opposite direction? What if most of these immigrants (legal and illegal) were likely to be Republicans in the near and middle term? Would the libertarian arguments for treating labor like any other economic good gain more traction on the right? I think so. Would liberals suddenly realize that they are undermining the economic standing of many African-American and working class Democrats? Almost surely.
Again, I don’t think the partisanship issue explains everything on either side. There are lots of good arguments for the Democratic and Republican positions that don’t hinge on this one variable. But I think single variables can have huge effects when changed. Anyway, we’ll probably never know, but it’s interesting to think about.