Pat Buchanan speaks of American conservatism in the past tense. "The conservative movement has passed into history," says the one-time White House aide, three-time presidential candidate, commentator and magazine publisher. "It doesn't exist anymore as a unifying force," he says in an interview with The Washington Times. "There are still a lot of people who are conservative, but the movement is now broken up, crumbled, dismantled." Mr. Buchanan, a former adviser to Presidents Nixon, Ford and Reagan, says conservatism "is at war with itself over foreign policy, over deficit hawks versus supply-siders." Unnamed phonies, he suggests, have infiltrated the movement....