It's either the primordial ylem or possibly the quintessential aether.I've noticed that too. If you look at a map of North America Mexico has blue stuff on it's left and right. I don't know what it means but tells me that you can't get there from here.
Either way, the MAGIC of the Trump Horizontal Monument will extend thousands of miles out from the coast and up to the Moon, effectively stopping all unauthorized human traffic and all illegal drugs from passing from Mexico into the United States. And with the Continental Army standing ready at the occupied airports, muskets loaded and primed, everything will be wonderful and America Will Be White Again!