Who are the extremists on immigration? To listen to mainstream media, you would suppose it was Republicans. And certainly Donald Trump’s proposals — to the extent that they are specific — and the large number (though not yet a majority) of votes he has been receiving in Republican primaries, provide some warrant for saying that Republicans have changed.

Every Republican presidential nominee from 1980 to 2008 favored some form of legalization and path to citizenship for illegal immigrants. Trump’s rhetoric suggests that he does not.