SAN LUIS — The first section of President Trump’s border wall in Arizona is rising near Yuma. After years of crowds shouting “build the wall” at political rallies and countless condemnations of the wall as xenophobic or a “vanity project” for Trump, the wall has taken the shape of square, metal poles jutting 30 feet up from the ground in San Luis, a border town south of Yuma. As early as this month, similar poles could rise along the Cabeza Prieta National Wildlife Refuge, Organ Pipe Cactus National Monument and across the San Pedro River. Despite the wall being the...