1. At low tide, you could walk to Mexico, around the crusty palisade of the border fence, without even getting your shoes wet. The thinnest can slip between the stakes, as kids do, dashing into America --'Look at me, mom!'-- and slipping back again over the line. The Pacific Ocean's relentless waves and salt spray have long ago eaten the fence's metallic flesh, leaving a disheveled skeleton of rusty spikes, 12 feet tall, like the broken and bent teeth of a giant scaly comb. ...