"The Rio Grande, what side of the river are you going to put the wall? We're not going to put it on our side and cede the river to Mexico," he [Secretary of Swamp property] said. "And we're probably not going to put it in the middle of the river."The river is most of the border, except California. There is no natural border between Alta and Baja California So the Trumpster has a bit of a geography problem, kind of like those folks making the California high speed rail.