Chile digs desert trenches along its northern border as President José Antonio Kast pushes a hardline migration crackdown critics say may have little effect. ARICA, Chile—Out on the wide open plain on Chile's northernmost coastline, dust billows in the cool breeze which sweeps across the pampa. In front of a row of concrete markers tracing the border with Peru, two sandy-yellow Chilean military excavators... [4703 chars]