Economist Bryan Caplan is doubtful about the perspicacity of voters when it comes to economics--yet as an open borders libertarian, he wants to increase the likely number of economically foolish voters. And he's OK with that:
Once you admit that (a) democracy does what voters want, (b) voters irrationally oppose markets and liberty, (c) voters from less pro-market and pro-liberty lands are probably even more irrational than we are, doesn't the case for strict immigration restriction readily follow?
1. Open borders are an extremely important component of the free market and human liberty. The labor market is roughly 70% of the economy. Labor is the main product that most people around the world have to sell. Immigration restrictions massively distort this market, and deprive literally billions of people of the freedom to sell their labor to willing employers. So even if open borders made all otherpolicies much less pro-market and pro-liberty, the (open borders + side effects thereof) package would almost certainly constitute a net gain for free markets and liberty.
2. The political effect of immigrants on markets and liberty is at worst modestly negative. The median American isn't a libertarian, and the median immigrant isn't a Stalinist. We're talking about marginal disagreements between social democrats, nothing more…
….perhaps it's best to respond to the political externalities question with another question: "If you favor markets and liberty, how can you oppose the deportation of the entire statist generation?" Native voters under 30 are more hostile to markets and liberty than immigrants ever were. Why not just kick them out? Part of your answer, hopefully, is that mass deportation would be a vastly greater crime against markets and liberty than anything voters under 30 are likely to manage. My position in a sentence, similarly, is that immigration restrictions are a vastly greater crime against markets and liberty than anything immigrant voters are likely to manage.
Caplan's reasons for doubting voters economic perspicacity were explained in his classic Reason magazine cover story from October 2007, "The Four Boneheaded Biases of Stupid Voters (And We're All Stupid Voters)."