By Ron Charles, The Washington Post When you wade into the ever-agitated waters of social media, you realize just how quickly the currents of infectious bile are flowing. Follow the tributaries of today’s political combat a few decades into the future and you might arrive at something as terrifying as Omar El Akkad’s debut novel, “American War.” Across these scarred pages rages the clash that many of us are anxiously speculating about in the Trump era: a nation riven by irreconcilable ideologies, alienated by entrenched suspicions.