Whence cometh the conviction, in America and even more in Britain and Europe, that open borders is the only moral immigration policy? Of course, not everyone believes that, and many who do stop short of saying so. But the contrast between the rhetoric and policies of the first two decades of the century and those that have prevailed since President Donald Trump’s election is unmistakable.

Presidents Bill Clinton and Barack Obama, like the George Bushes, professed to want to enforce immigration laws. They decried the flood of illegals that crested in the prosperous decade before the financial crisis, and afterwards saw with relief that the flow of illegals slowed.