When, five years ago, Hillary Clinton announced the existence of a "vast, right-wing conspiracy," conservatives responded with hoots of derision and laughter. The very idea was preposterous. Or was it? Recent developments suggest she may have been prescient. Once a week a couple of dozen leaders of conservative groups gather at the offices of Grover Norquist, head of Americans for Tax Reform. Every few weeks the National Republican Congressional Committee convenes a group of senior Republican consultants and operatives, most of them veterans of many campaigns. Why else would these groups meet regularly unless it is to plot the nation's...