Cornyn should have explained the Texas border with Mexico. For most of the border, the Rio Grand river is the divider between the two. We own half the river and Mexico owns the other half. If we put a wall on our land next to the river, our ranchers can't get the water. We can't put a wall on the Mexico side because that is their land, not ours. We can't put a wall in the middle of the river. The first place the river is not the divider is nearing El Paso, almost out of Texas.
Trump went to Texas during the campaign, saw the river dividing the two, and said sometimes a wall won't work. That statement fell by the wayside, but the truth is still there.
