the problem lies within the political minds. I admit I haven't seen a smidgen of the border and where it lies. But I'd surmise some of the border is near cities/towns on both sides of the border.
TheDonald's brilliant mind see's both Mexico and American town/cities near the border could use the solar power. Who but some, will say TheDonald said the "entire" border will be made of solar panels? The Liberal Democrats/Media will say that's what Donald actually meant. Come on Now!