Just to be clear: is that just a snide comment, or do you really figure that for some reason (which I hope you can explain to me) there are many Mexican illegal immigrants who are pretending to be from some other Central-American country?

Fair enough I suppose, except that I don't much identify with the Democratic side of the aisle, or with Obamacare. Or in fact with the whole concept of dividing everyone into just two camps.

It's just common sense that even on topics where you can more or less divide people into just two camps, like immigration, there is still a wide range of opinions on each side. Just look at all the research into how opinion poll results can differ significantly depending on the exact phrasing of any given question, or on which information is and isn't mentioned. So yeah, without pretending to be able to speak for those people in 'your group', I'm still very confident that the group is not monolithic, and that some of them would in fact change their mind if they see the cost of their desired solution is much higher than they figured.

You'll note that the only policy I was criticizing was Donald Trump's, if you can call that a policy, and that you yourself admitted you didn't believe that all illegal immigrants would be expelled. If Donald Trump had a policy that was actually realistic, I would probably still criticize it, but less harshly and I would indeed need to do a lot more research first.

Certainly there are costs, to society as a whole and most of all to low-educated Americans facing unfair competition in the job market. But there are also important benefits - not only to those profiting from illegal labour, but also for society as a whole which sees lower prices for all sorts of products and services as a result, plus all the sales taxes that the illegals do pay (it's not as if they would pay much income tax even if they were legal, with the incomes they make).

I'm sure that in some places, the costs still outweigh the benefits, and people really would be better off with the illegal immigrants gone. But even so, removing them all at once would be a painful adjustment, with employers unable to replace them all overnight and taking heavy hits in the short term, to say nothing of the law enforcement costs involved for such operations. Illegal immigration increases and decreases naturally over time - more modestly scaled targeted expulsions combined with better immigration control (not just border control - a huge share of illegal immigration is due to overstaying visas and would be completely unaffected) should solve the problem well enough. And while I don't have a strong opinion personally about the laws making everyone born on American soil a citizen, as long as they exist it is indeed difficult to implement policies separating parents from their children.

See above. And it's not so simple with unemployment - yes, illegal immigration depresses wages for low-educated Americans, but that doesn't mean if you kick them out you can just directly transfer their jobs to unemployed Americans (I'll just give you the benefit of the doubt on that 'English speaker' bit). Many of their jobs would simply disappear, with the employers going bankrupt or being forced to start doing the same work with far fewer, higher-paid employees - good news for the employees in question, not so much for the employer or for the broader population buying his products.

Would you really want a populist, incompetent egoist like Trump to get into the White House, do little of use, and kill off the Republican majorities in Congress as a consequence?

Really not following you there. Voters who are already disappointed and will get even more disappointed if they elect Trump - how would that be a good thing?