CACTUS, Texas — The streets of this small, isolated city in the Texas Panhandle are virtually empty nowadays, and “For Rent” signs decorate dilapidated trailers and shabby 1940s-era military barracks that just weeks ago were full of tenants. Sales of tortillas and other staples are down. Money wire transactions to Central America have mostly dried up. The “Guatemalas,” as local residents call them, are almost all gone...........