Trump's remarks risk upending his entire case for declaring a national emergency. He imagines how a Democratic president might declare a national emergency to achieve stricter firearms control, for example. Eight prototypes for the border wall stand in San Diego in 2017, awaiting tests to determine how easily they could be tunnelled under, climbed over or chiselled through. "It's one thing to declare a national emergency if you think there are foreign troops at the frontier. Watch Trump declare a U.S.-Mexico border emergency:

Source: CBC News February 16, 2019 09:00 UTC