The most important obstacle for Trump’s strategy is that it violates what many experts describe as the first rule of negotiation: never to take a hostage that you can’t harm. Put another way that means negotiators should never to make a threat that they can’t fulfill. Yet Trump’s threats, if fulfilled, would cause at least as much pain for his allies as his adversaries.

In a recent Quinnipiac University national survey, nearly 90% of Americans said the young people brought to the country illegally by their parents should be allowed to stay; even four-fifths of Republicans agreed. By contrast, 60% of Americans opposed Trump’s border wall, which he has insisted Democrats accept as the price for maintaining the deferred action protections.

On health care, a recent survey by the non-partisan Kaiser Family Foundation found that 60% of Americans say they will hold Republicans accountable for the ACA’s future performance.