Leonard Pitts: Barriers zigzag across America like a scar

A few words about walls.Unsurprisingly, the one Donald Trump is trying to build on the southern border — the one he swore Mexico would pay for — has proven, like most things he touches, an embarrassing failure. First came news early this month that smugglers have been able to cut through the barrier with a simple reciprocating saw, available at Home Depot for prices starting at less than $100. Then, TBS’ “Full Frontal with Samantha Bee” aired a segment demonstrating