On a dirt road below the shrub-dotted hills of Arizona, Donald Trump used a stretch of wall and a pile of steel beams to draw a visual contrast between his approach to securing the border and that of his Democratic opponent, Vice President Kamala Harris. Trump brought along grieving mothers, the sheriff of Cochise County and the head of the Border Patrol union to echo his tough-on-border security message at Thursday’s visit, which was themed “Make America Safe Again.”