Donald Trump’s promise to build a wall along that troublesome border with Mexico was a factor in his surprising election as President of the US in 2016. The primary influence in today’s setting often seems to be what’s good for me and mine. No less than an academically trained author and scholar—Heather MacDonald of the Manhattan Institute, who earned a B.A. from Yale, an M.A. from Cambridge, and a J.D. from Stanford Law School—wrapped up a speech in early 2015 with this frank declaration: “Immigration