Central American immigrants ride north on top of a freight train
on Aug.   near Juchitlan, Mexico. Thousands of Central American
migrants ride the trains  during their long and perilous journey
north through Mexico to reach the U.S. border.  A cloud of slow
moving dust is approaching. I'm on Highway 9, the narrow east-
west road from Columbus, N.M., to El Paso, Texas, a road that
parallels the U.S.-Mexico border cutting through a wasteland of
cactus, lava-like rock and scattered mesquite bushes.  It's a
Border Patrol vehicle towing what we used to call a "tooth
harrow" when I was growing up in western Colorado. It's used to
break up manure after cattle had been grazing in our pastures.
A swath about 30 feet wide has been cleared on the south side of
the road extending most of the 65 miles from Columbus to the
intersection just west of El Paso. The border patrolman is going
slowly in the opposite direction so there's no way to ask how
much of this 65 miles has to be harrowed or why it is being
done. To spot th