5/19/16 New York Times
Big promises are to be expected from presidential candidates, but reality often intrudes. The elder George Bush broke the “no new taxes” pledge that helped lead to his election. And Barack Obama’s administration has yet to live up to his prediction that his nomination would go down in history as the moment “when the rise of the oceans began to slow and our planet began to heal.”
Donald J. Trump’s vow to restore what he says is America’s lost luster, while perhaps not as flowery, comes with campaign promises that are equally grandiose. But Mr. Trump, the presumptive Republican nominee, has typically provided scant details on how he might make good on his promises — and ambitious ideas, even the concrete kind, do not always add up.
Central to Mr. Trump’s campaign, and to his national security strategy, is his intent to clamp down on illegal immigration, using a vast deportation “force” to relocate people to the other side of a wall, funded by Mexico, that would stretch nearly the length of the southern border.
Mr. Trump has suggested he will flesh out his ideas in a forthcoming speech. But experts across many fields who have analyzed his plans so far warn that they would come at astronomical costs — whoever paid — and would in many ways defy the logic of science, engineering and law.