It is a huge problem with the Latino acceptance statement. It will make the difference between loss and another round in the White House. If you wish to continue, you have to make a strategical reorganization of your statement. I do not say this to value the ethical content of the political principle, it is only a strategical perspective.
You can discuss it in terms of a conservative strategy; According to both Plato and Aristotle, the discussion of the citizenship and the sacredness of it, is a vital principle to adher to. According to Aristotle a new citizen would take around five generations to really be a part of the polis. Things were different i Athens, but still it makes a point, a citizenship is a very dear commodity to give away. The Roman Empire fell, when there were no more roman citizenships to give away to the Empire, because everybody had it.
Now, if you want to make a strategical drawback, do it with a lot of grace, otherwise it will be a mess. Do it in order to mollify and pacify the conservative voices in your own backyard. It will cost you in terms of critical voices, but it will allow you to win a lot of the silent protesters of the chaos, that the US is witnessing in some of the more vulnerable states.
When a democracy is in chaos, people will look for order and ethics. So if you want to win, you have to give them that.
Sorry, it is not an ethical stance it is a realistic assesment of the situation.
Romney seems to have picked up the renaessance ideas that I have tried to spread, this will make him a very succesful and difficult opponent to beat.
Good luck, and G-d bless you.