Anyway, I'm still poking around, but I find myself again leaning toward Bill Richardson's camp. Of the candidates I've watched on immigration, he's the only one to appropriately reframe the issue.
Every time the democrats say "border security" or "secure our borders", they're reinforcing the message that A) we're under threat from immigrants B) the threat we're under is a security threat and C) we can secure our borders.
Regardless of how you feel about immigration, anyone who's remotely informed understands that it is an economic issue. Border security does have an effect of course — it increases the number of deaths at the borders and it likely increases profits for coyotes (who may in fact be bad people). The one effect it certainly does not have is to reduce the number of undocumented immigrants coming into our country.
Richardson reframes the issue, calls the media on their racist crap, and suggests that if we want to reduce the number of immigrants, we need to start talking with other countries about job creation (i.e. we need to address the economic imbalance that leads immigrants to come here).
So here's a question: does Richardson have a chance? Are there reasons not like him as a third option (so far I'm inclined not to like Hillary because she's not a good enough orator and not to like Obama because he seems a little fluffy to me as of yet).
On a semi-related note, if you haven't seen this calculation, you should -- it's a simple bit of analysis quantifying just how much of a jerk you have to be to oppose immigration to the U.S.