One year into Donald Trump’s second reign, it is easy enough to argue that, in a short while, there won’t be much of an American republic anymore. Not long before he died in 2012, Gore Vidal predicted the United States would eventually backslide into a military dictatorship. The celebrated author and intellectual was a declinist by nature, and he was musing about the collapse of democracy before Trump even rode down his golden escalator. Vidal’s observation was that the postwar American empire naturally strangled popular institutions. Each president seemed to be more imperial than the last and now had in...