There’s a virus infecting our politics and right now, flourishing with a scarlet heat. It feeds on fear, paranoia and bigotry. All that was required for it to spread was a timely opportunity — and an opportunist with no scruples.There have been stretches of history when this virus lay dormant. Sometimes it would flare up here and there, then fade away after a brief but fierce burst of fever. At other moments, it has spread with the speed of a firestorm, a pandemic consuming everything in its path, sucking away the oxygen of democracy and freedom.Today its carrier is Donald Trump, but others came before him: narcissistic demagogues who lie and distort in pursuit of power and self-promotion. Bullies all, swaggering across the landscape with fistfuls of false promises, smears, innuendo and hatred for others, spite and spittle for anyone of a different race, faith, gender or nationality.