FWIW, having now read through the thread, I think a lot of hay is being made about Trump's statement resembling the prototypical "why don't you go back where you came from", and in its classic form I do agree with the liberal posters here that this is clearly a racist (or at best a something-ist) formulation. What Trump said shares some characteristics with this and on those ground borders on being an 'homage' to that racist formulation. The actual statement in context, however, seems to be saying that people who want to use distorted ideas of how to help a country should go try them elsewhere prior to ruining America with them. Of course that line could only work on someone whose ancestral nation is in bad shape, since for instance telling Bernie to go and fix Denmark prior to trying his 'socialist' ideas in America would be nonsensical. So while crude, Trump's basic message seems to be "your ideas are a joke, since other countries that use them have gone to hell." I mean, that's not a nice thing to say anyhow, and it does take on a very standard Republican trope, which is that socialism is evil because something something Russia and Venezuela. I think it's a silly argument, and my first take on Trump's comment here is that he's using a mindless soundbyte-type dismissal of people in a crude away - basically his entire rhetorical strategy going back to when he was essentially insulting Jeb Bush's face.
I am a little surprised that some people here are trying to defend the "go back to the country you came from" line as not being racist in regards to American citizens, notwithstanding that this isn't really what Trump said in this case. If he *had* said that it would look a lot worse to me and would be very hard to defend. As it stands it's only hard to defend.