When you don’t have a real border, because you don’t have enough people to enforce it, and won’t build a fence to help them, you get fearful citizens, arming themselves a hundred miles from the Rio Grande:
"If it was the immigrants of old there’d be no fear; you’d live and let live. If they wanted to improve their lives that’s fine. Before, the travelers came alone or with one or two of their family, and they were humble, polite. Now they come in packs. They’re desperate, bold. A lot of them are pretty well dressed, and everyone seems to want to go to Houston. It’s a completely different element."
From The Immigrant Graveyards of South Texas, a long read but an uncommonly good one from the Texas Observer. Via AlterNet