In any other presidency, the story would rock the United States: Washington's most senior national security advisers having a highly confidential discussion about plans for the US to launch military strikes, and every word of it being read by an astonished journalist. But in these times of the New World of Donald Trump it was seen as yet another day — a story that might run for a few hours before blowing over. Washington is not what it used to be. When news emerged that The Atlantic's editor-in-chief had been accidentally included in a group chat about a plan to…