Like Milbarge at BTQ, I endorse pretty much all of Hei Lun at BTD's post about immigration policy reform, though with one addition and a few exceptions.
Addition: A guest worker program is bad not only because it's unlikely to replace illegal immigrant labor absent heavy enforcement of laws against hiring undocumented workers, but also because we don't want to create a second class of residents as European nations have done. After all, what are we going to do with children born of guest workers who automatically have citizenship rights under our current Constitution? Which brings me to the first of my exceptions:
Hei Lun recommends that we have no form of amnesty and instead make people who entered the U.S. illegally go to the back of the line for re-admission to the country. I agree that the current de facto system -- in which those who can drive over the border come in, while those who would need to take a flight, a long boat ride or a really long swim have to wait for years to get a visa -- is geographically unfair. My parents entered the U.S. legitimately and we have many relatives who would like to do the same, and part of the reason Congress feels political pressure to restrict the number of visas excessively (i.e. a number much lower than the demand from employers even for skilled workers) is that many of their constituents already feel that there's too much immigration due to the level of illegitimate entry.
However, Hei Lun's idea that we should categorize people who entered illegally several years ago in the same way as someone who comes tomorrow ignores practical reality. People with longtime residency have borne children who are U.S. citizens and established meaningful lives in their communities, as Hei Lun's fellow blogger points out. I strongly support prohibitively heavy penalties on employers for hiring illegal immigrants, but we need to make a reasonable cutoff point instead of lumping all such immigrants together. I would be fine with putting in place legislation that provides current illegitimate residents a path to legitimacy along the lines of the Senate plan, so employers can keep the workers that they already have, while instituting extremely harsh laws against hiring any new ones. In effect, this means that we would provide current residents with modified Social Security numbers that would identify them as illegal entrants on the path to citizenship and would create a system to verify such identities to eliminate excuses that the documentation looked OK. Any employee found in a workplace without an SS number that checked out would be immediately deported, the institutional employer fined and the person responsible for the hiring prosecuted.
The remark about unprotected borders that focuses on Mexico makes a common error: the assumption that terrorists are likely to come through there. On the contrary, we probably need to focus more on our northern border if it's really terrorists we're trying to block; without being a self-hating South Asian, I'll admit that anti-American terrorists are more likely to share my ethnic descent than Deysi Ramirez's.
Though not precisely aligned with the "brain drain" concerns about educated immigrants' leaving developing countries*, Hei Lun's saying, "I don't know whether it's good for Mexico that they lose millions of their hardest workers to another country" is a similar idea, though less focused on the loss of intellectual capital. Looking at India, it's hard to see it as much of a problem; lots of talented and hardworking people stay, especially when the remittances by non-residents turn into investments and the country becomes a better place to live. (Incidentally, India Today also frets about the "brain drain" caused by outsourcing, in which educated people stay in the country but work in jobs that don't require their highest level of skill, while leaving unfilled jobs in research and development that pay less but would help their country more.)