Two hundred miles north of the border, Sheriff Roy Boyd of Goliad County, Texas, has placed warning signs at his county line, written in Spanish. “Warning! Drug and human traffickers: Turn around, do not enter Goliad County,” the sign reads. “Go around. Otherwise, we are going to hunt you down and put you in Goliad County jail.” He says they work. When the signs are up, cartel activity decreases, and when the Texas Department of Transport removes the signs, cartel activity picks up again. “When the signs are in place we notice that we do not have fresh activity at the thirteen stash locations that we are monitoring in Goliad County,” Boyd wrote on Facebook. Goliad County issued a local state of disaster on April 21 due to the impact of the border surge. Boyd said the county, with a population of 7,600, is used by cartels as a staging …