Beyond keeping out bugs, the screen door safeguards Americans' trust in others

ANN ARBOR, Mich. (AP) — The metallic screech followed by a sad excuse for a bang. The tap-tap-tap of a cat eager to come in before dusk. The erratic thumping of moths doomed by the siren-pull of the kitchen light. Morning brings the soft knock of a neighbor, friend or relative who knows there is no need for the formality of ringing a doorbell.The screen door, despite — or thanks to — its modest making, is fundamental to the American home, to the suburban and rural soundscape and to what remains of our collective innocence.The door that is barely a door. Made of lightweight aluminum or wood, with a wire mesh and a latch lock that gives under a thumb nudge, it is about as shabby as a barrier gets. Its mission to let the breeze in and keep the mosquitos, pesky flies and assorted vermin out ap