[harshreality]

The desire to "build a wall" is a reaction of locals along the border to the realities there, and that reaction diffuses through the rest of the population who aren't on the border but who see problems that they perceive (or are persuaded to perceive) might be solved by curtailing illegal immigration. They may be wrong about, or miscalculating, the ultimate consequences of a wall, but the perceived need for some kind of "wall" is coherent in an immediate sense.

What do you think is incoherent? A plan to build some kind of physical wall (barrier), or a serious plan to keep people from crossing the border outside of the normal immigration process, or both?