NOT since the 1960’s has the course of public policy seemed more under the influence of ideas and so, presumably, of intellectuals. The two periods are different, of course. In the sixties, the ideas in question were those of liberal intellectuals and, since liberalism has long been the governing ideology of American politics, the intellectuals then in vogue were brimming with the kind of self confidence that comes from the belief that they were in the vanguard of an irresistible historical impulse. Today, the ideas that seem to influence the administration of President Reagan are about how best to reverse, or at least stem, a political tide that has been running for half a century or more. Not surprisingly, these ideas are more controversial and their proponents feel more embattled than did their predecessors of two decades ago. In the 1960’s, the “policy intellectuals” saw themselves as priests of the established order; today, their counterparts think of themselves as missionaries in a hostile country.