Portable helicopter landing mats designed for Vietnam have been reused to build large sections of the US-Mexico border wall. The Army Corps of Engineers provided institutional links between these two geographically distant imperial projects. After documenting the historical connections between war and wall, I shift the analytic lens to show how mid-century modernism and imperial foreign policy were entangled aesthetically. General Westmoreland, Agnes Martin, Sol LeWitt, and Richard Serra all draw from the same social imaginary. Substantive political disagreements notwtihstanding, geometric grids animated aesthetic affinities that have made it more difficult to perceive, let alone critique or dislodge, the long tentacles of American imperialism.