WASHINGTON — It is easy these days to imagine that one is living in a fairy tale, albeit a dreary one. In fairy tales, as in Washington, things are true that can’t possibly be — and what is not true can be defended by tilting the facts a certain way and catching the light just so. Objective truth, it seems, has gone the way of trolls, goblins and gremlins, by which one should not infer that Truth has taken up residence in the U.S. Congress.