We rarely pause to consider what liberals have lost by neglecting a common intellectual heritage.
Ask Republican vice presidential nominee Paul Ryan how he became a conservative and he'll probably answer by citing a book. It might be Ayn Rand's "Atlas Shrugged." Or perhaps he'll come up with Friedrich Hayek's "Road to Serfdom," or even Barry Goldwater's "Conscience of a Conservative."
All of these books are staples of the modern conservative canon, works with the reputed power to radicalize even the most tepid Republican. Over the last half-century, they have been vital to the conservative movement's success - and to liberalism's demise.
We tend to think of the conservative influence in purely political terms: electing Ronald Reagan in 1980, picking away at Social Security, reducing taxes for the wealthy. But one of the movement's most lasting successes has been in developing a common intellectual heritage.
Any self-respecting young conservative knows the names you're supposed to spout: Hayek, Rand, Ludwig von Mises, Albert Jay Nock. There are some older thinkers too - Edmund Burke, for instance - but for the most part the favored thinkers come out of the movement's mid-20th century origins in opposition to Soviet communism and the New Deal.
Liberals, by contrast, have been moving in the other direction over the last half-century, abandoning the idea that ideas can be powerful political tools. This may seem like a strange statement at a moment when American universities are widely understood to be bastions of liberalism, and when liberals themselves are often derided as eggheaded elites.
But there is a difference between policy smarts honed in college classrooms and the kind of intellectual conversation that keeps a movement together. What conservatives have developed is what the left used to describe as a "movement culture": a shared set of ideas and texts that bind activists together in common cause. Liberals, take note.
Once upon a time, the Old Left had "movement culture" par excellence: to be considered a serious activist, you had to read Marx and Lenin until your eyes bled. For better or worse, that never resulted in much electoral power (nor was it intended to) and within a few decades became the hallmark of pedantry rater than intellectual vitality.
The New Left reinvented that heritage in the 1960s. Instead of (or in addition to) Marx and Lenin, activists began to read Herbert Marcuse, C. Wright Mills and Saul Alinsky. As new, more particular movements developed, the reading list grew to include feminists, African-Americans and other traditionally excluded groups. This vastly enhanced the range of voices in the public sphere - one of the truly great revolutions in American intellectual politics.
But it did little to create a single coherent language through which to maintain common cause. Instead, the left ended up with multiple "movement cultures," most of them more focused on issue-oriented activism than on a common set of ideas.
Liberals have channeled their energies even more narrowly over the past half-century, tending to prefer policy tweaks and electoral mapping to big-picture thinking. When was the last time you saw a prominent liberal politician ascribe his or her passion and interest in politics to, of all things, a book?
Liberals may argue that they are better off knocking on doors and brainstorming policy than muddling through the great works of midcentury America. "Americans usually reject the party of theory," E.J. Dionne wrote in Sunday's Washington Post, responding to Ryan's nomination, "which is what conservatism has now become."
The problem is that most liberals couldn't put together the sort of intellectual short list that conservatives now take for granted even if they wanted to.
In my Yale seminar on liberalism and conservatism, I try to assign some plausible candidates: Arthur Schlesinger, Reinhold Niebuhr, Betty Friedan, Michael Harrington, Martin Luther King, John Kenneth Galbraith. Undoubtedly many people reading this essay can come up with alternatives, but liberals rarely ever have the conversation.
Putting together the conservative side of the syllabus is always vastly easier than putting together the liberal one, in part because conservatives themselves have put so much time and energy into the selection process.
Some of this imbalance is due to the relative weakness of the current American left. Liberals are not the logical counterweight to conservatives; leftists are, but they are few in number. Still, we have the political spectrum that we have, and liberals fail to take up the intellectual challenge at their peril.
Conventional wisdom suggests that Romney may have doomed his electoral bid by choosing an ideologue - one who likes to go on about Ayn Rand! - as his vice presidential nominee. Yet it is possible that Ryan's nomination will do just what Romney wants: mobilize a base of committed activists who share most of Ryan's basic ideas.
The default mode for liberals and progressives in such situations has often been to celebrate "diversity" - intellectual, racial, sexual and of most other sorts. In many ways this is for the best. Nobody wants to return to an era in which politics and political ideas were dominated by a handful of white men, however thoughtful.
Yet we rarely pause to consider what liberals have lost by neglecting a common intellectual heritage and by attempting to win political success without a political canon. At its best, a canon helps people put the pieces together, offering long-term goals and visions that sustain movements through periods of trial and defeat.
Without those visions, liberals have no coherent way of explaining where we're headed, or of measuring how far we've come.
Betty Gage, a Yale history professor, is the author of "The Day Wall Street Exploded."
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