All across the Pampas, in one wind-swept little farming town after another, a sense of dread has suddenly set in. Mauricio Macri, the man who championed the cause of the Argentine farmer, is almost certain to lose his re-election bid in October and will hand back the presidency to the leftist party that tormented the region for years. A primary vote held a few weeks ago made that clear. The concern is so severe that many here aren’t waiting for the actual election to confirm Macri’s defeat. They can’t,…