Re: policy being legal
How about "Build a wall and make the Mexicans pay for it"?
Amazingly, the Mexicans would pay - in their droves - for an opportunity to see Donald Trump himself, and no other, build his fabulous wall, from shore to shore, in a colourful orange jumpsuit and trowel and cement blocks and mortar in his hot little hands. Mexico's drug gangs might even stop their drug wars to tour the border and watch @realDonaldTrump do some @realWork @forReal @forOnce!!!
I think the Mexicans should be given the opportunity to see such an event. There should be some impresarios in Mexico City who'd leap at the opportunity to stage such a tourist event.