President Trump is setting in motion Tuesday the worst defeat for the immigration-control cause since President George H.W. Bush signed into law the 1990 Immigration Act, doubling U.S. immigration quotas. But while the elder Bush understood what he was doing, Trump does not. The 1990 law operated precisely as its authors intended and expected. Today’s immigration actions will produce results almost directly opposite of those advertised. It will lead to more and larger amnesties in the future, and then to larger and less-controlled immigration flows after that.

President Obama issued the order known as DACA (“deferred action on childhood arrivals”) in 2012 after failing to achieve his hopes of a broader amnesty. Obama himself had repeatedly denounced the concept as beyond presidential power…

Latino enthusiasm for Obama had faltered through his first term, a casualty of the slow economic recovery. Failure to produce some kind of immigration deal might well jeopardize his re-election. (In the end, Hispanic voter turnout dropped between 2008 and 2012, from 49.9 percent to 48 percent.)