Half a century ago, in liberalism's heyday, American conservatism seemed a contradiction in terms. Men of genuine and liberal learning (was there any other kind?) assured one another that the United States is, was, and ever would be a liberal society. They defined liberalism in an easy-going, open-ended way, connecting the New Deal to the American Revolution by a more-or-less straight line, defined less by philosophy than by temperament: the readiness to change, to experiment, to reinvent—both the government and the self.

In various ways, Louis Hartz, Lionel Trilling, Arthur Schlesinger, Jr., and others drove this lesson home. For better or worse (most thought for the better), America was the land of liberalism. Conservatism was at best liberalism's shadow ("the thankless persuasion," Clinton Rossiter called it) and at worst a European affectation, at once aristocratic and ridiculous. American conservatism was inarticulate—"bookless," John Kenneth Galbraith once remarked acidulously—because it had nothing to say either about or to America.

With his usual acuity, Galbraith's pronouncement came in the midst of the century's greatest outpouring of conservative books. The 1950s and 1960s saw the publication of classic works by (to name a few) Friedrich Hayek, Milton Friedman, Russell Kirk, Richard Weaver, Robert Nisbet, Eric Voegelin, Leo Strauss, Harry V. Jaffa, Edward C. Banfield, Whittaker Chambers, and William F. Buckley, Jr. Subsequent decades added luster, with James Buchanan, Thomas Sowell, Charles Murray, James Q. Wilson, Allan Bloom, Walter Berns, Irving Kristol, Norman Podhoretz, and others joining the fray.

So, who's bookless now? The publisher of the New Republic, no less, admitted recently: "It is liberalism that is now bookless and dying." 

"Who is a truly influential liberal mind in our culture?" Martin Peretz asked. "Whose ideas challenge and whose ideals inspire?… There's no one, really. What's left is the laundry list: the catalogue of programs…that Republicans aren't funding, and the blogs, with their daily panic dose about how the Bush administration is ruining the country."

In fact, the exhaustion of liberal ideas started long ago: modern liberalism peaked intellectually in the first half of the last century. By the century's end, so many progressive ideas had been written into law, with such mixed results, that liberals remain bewildered and even to a degree disillusioned by their own successes, not to mention their multiplying electoral defeats. Their glory days seem behind them. If "the era of big government is over," after all, where do liberals go from here? 

Think twice before gloating, however. After victory in the Cold War and the death of many of conservatism's founding fathers (especially Ronald Reagan), one senses on the Right not only a generational shift but also a growing distraction or inattentiveness, as though the campfires are burning down.

The two developments are related, in part. George W. Bush's administration is by some measures as conservative as Ronald Reagan's, but its spirit is quite different. Reagan and his administration were shaped by the clash between regnant liberalism and the plucky conservative opposition. Bush's administration inherited Reagan's triumph and liberalism's senescence. As a result, Bush can assume, politically speaking, much that Reagan had to argue; and the president can take for granted, alas, much that Reagan always championed, like the case for limited government.

This decline is visible in conservatism at large, too. It is one thing (a blessing, I can tell you) to grow up reading and watching Bill Buckley; another to grow up reading and watching Bill O'Reilly.

Bush's lapses are not comprehensive, of course. He cut taxes. He has ordered heroic actions that Reagan never had to. And his reliance on natural rights brings Bush closer at least to the American Founding than many old-school conservatives ever got, despite their constant appeals to it. 

Nonetheless, the danger of taking our precepts for granted—of forgetting the thinkers and arguments that made possible the epic confrontation with liberalism—grows greater as American conservatism moves farther away from its own founding age. We need to recur to first principles if we are not to lose sight of our purposes. 

But then one of the spiritual advantages of conservatism is the confidence that all is never completely lost or won. There is no such thing as saving civilization, once and for all. It is a never-ending challenge. Though the finest books may fade and be forgotten, truth endures, awaiting rediscovery. Most liberals, by contrast, believe fervently in mankind's evolution, in every sense of the term. Once shake their faith that history is necessarily on their side, and they are left unmanned—and bookless.