President Donald Trump called for a huge overhaul of the nation’s immigration rules to reduce the huge inflow of low-skill, welfare-dependent immigrants, but perhaps also to increase the inflow of productivity-boosting white-collar immigrants. In his Feb. 28 speech to the joint session of Congress, he declared: Nations around the world, like Canada, Australia and many others –- have a merit-based immigration system. It is a basic principle that those seeking to enter a country ought to be able to support themselves financially. Yet, in America, we do not enforce this rule, straining the very public resources that our poorest citizens...