We live in an age of what historian Thomas Frank calls instant forgetting. It’s not just that we forget things—it’s that we seem to replace the past with inexplicable fictions.

Take how Americans remember the previous president. In December, it was reported that George W. Bush’s Gallup approval ratings had risen to 47 percent. That represented a dramatic increase from his ratings in office, which by his last year never broke 35 percent—a befuddling improvement considering nothing about his legacy has changed in the years since he left office.

Let’s chalk it up to a decent society’s magnanimity. But how to explain the short-term memory loss that has gripped the public when it comes to the ideas Bush stood for? The first two years of the Obama era have brought something many liberals did not expect: the revival of a conservative economic philosophy that had been thoroughly discredited by the eight years of Bush—or so we thought.

That renewal casts a pall on this era. For as fruitful as President Obama’s Administration has been, it would be hard to argue that his legislative triumphs have been accompanied by a renascence of public progressivism. Somehow the old, tired mantras of a bankrupt ideology—smaller government, deregulation, tax cuts above all—have carried the day in our discourse. Americans, it would seem, have already forgotten what got us in this mess in the first place.

These episodes of forgetting get at something fundamental: Americans are simply not very good at history. If, as Harry Truman said, the only thing new in this world is the history you don’t know, then Americans are always discovering new things—new, erroneous things.

But there is a deeper failure in this forgetting. Beyond the circumscribed world of academic journals and conferences, history is being taught—on TV and talk radio, in blogs and grassroots seminars, in high-school textbooks and on Barnes & Noble bookshelves. In all of those forums, conservatives have been conspicuous by their activity—and progressives by their absence. What accounts for the complacency? Our victories in the culture wars, eloquently recapitulated by Ethan Porter in these pages last summer [“V-Day in the Culture Wars,” Issue #17], have perhaps made us lax. Or maybe our reality-based orientation, our serene confidence that the facts will out, explains it. Surely, we tell ourselves, no one can challenge what actually happened?

Yet that is exactly what the conservative movement is doing, and has been doing, for decades. Theirs is a crusade to explain American history from conservative premises. It is a dogged campaign that they have been waging—and winning.

The failures start at the top. Barack Obama has, without doubt, governed as a successful progressive president. From health care to financial regulation to the repeal of “Don’t Ask, Don’t Tell” to the largest stimulus in history, Obama has accomplished a great many things in the face of record-breaking obstruction from an ever-more radical Republican Party. But in one crucial regard, he has been found wanting: He has failed to contextualize his victories in a larger progressive history.

It’s an ironic failure. Barack Obama may have rocketed to political stardom with his speech at the 2004 Democratic National Convention, but it was another address—one devoted to a retelling of history—that made many progressives sit up and take notice at the beginning of his national career. On June 4, 2005, then-Senator Obama delivered the commencement address at Knox College in Galesburg, Illinois. It was a masterpiece of a speech, and it offers now what it offered then: a tantalizing glimpse of an Obama presidency that could tell a good story about progressivism.

The speech was a departure in more ways than one. For one thing, it generally eschewed the platitudes of the dreaded genre. It exhorted and inspired, of course, but it also spent most of its time folding the achievement of the class of 2005 into a larger story. Ruminating on the absurd question that had been asked him by a reporter upon his election—“Senator Obama, what’s your place in history?”—Obama told the students that for most of human history, the individual had little say in answering that question. “And then,” he said, “America happened.”

What followed was a bracing story of the American experience that drew a direct line from the founding through the Civil War, the Great Depression, World War II, and the civil rights movement, right up to the challenges of the present. But it’s the prism through which Obama invited his listeners to view this past that made the speech stand out. For in recounting the past, Obama articulated—beautifully—a progressive vision of history. At every turn, when confronted with a crisis, what did Americans do? “We chose to act, and we rose together,” he said. His was a vision of a nation that picked its town-hall, rather than rugged-individualist, traditions when confronted with moments of reckoning. And he called on the students of Knox College to find that tradition again to bring America into a new millennium.

But even more rousing was his juxtaposition of that progressive tradition with the conservative one. The address was unusual for Obama in its willingness to engage ideology directly. He invoked Bush’s “ownership society,” noting that “in our past there has been another term for it—Social Darwinism, every man or woman for him or herself.” But Obama said this outlook was problematic. “It won’t work,” he said. “It ignores our history”:

It ignores the fact that it has been government research and investment that made the railways possible and the Internet possible. It has been the creation of a massive middle class, through decent wages and benefits and public schools, that has allowed all of us to prosper. Our economic dominance has depended on individual initiative and belief in the free market; but it has also depended on our sense of mutual regard for each other, the idea that everybody has a stake in the country, that we’re all in it together and everybody’s got a shot at opportunity.

Here was Obama saying, flat out, that conservatives were wrong, that they misread our history. And here was a narrative for progressives to latch onto, to repeat to each other and to their fellow Americans: the notion of a common good, central to progressive thought, pervading the American past.

When he ran for president, part of what I found exciting was the idea that we finally had a standard bearer who could tell the story of the progressive American past so well. But the sense of mission in that speech at Knox College hasn’t been sustained in his years in office. Many on the left have complained about his ability to put forward a narrative, and his dropping of history as a subject for lecture is part of that. The irony is that Obama, once feared to be too professorial for the public, turns out to be not professorial enough for our tastes.

To be sure, Obama has revisited the themes of the Knox College speech every now and again, most explicitly—and most movingly—during the health-care address he delivered to Congress in September 2009. Reflecting on a letter Ted Kennedy wrote him before he passed, the President entreated his fellow Americans to see that the liberalism underpinning health reform was consistent with, and a product of, American history:

This has always been the history of our progress. In 1933, when over half of our seniors could not support themselves and millions had seen their savings wiped away, there were those who argued that Social Security would lead to socialism. But the men and women of Congress stood fast, and we are all the better for it. In 1965, when some argued that Medicare represented a government takeover of health care, members of Congress, Democrats and Republicans, did not back down. They joined together so that all of us could enter our golden years with some basic peace of mind.

It is a history lecture that stands out, precisely because we hear it so rarely.

But it’s not just Obama’s failure. This is a larger failure on the part of progressives as well. We simply haven’t shown as much interest in recounting as conservatives do. Part of it may be the progressive orientation—our eyes are always cast toward the next horizon, not the one behind. Part of it may lie in what a Bush aide told journalist Ron Suskind, in what has now become a classic summa of modern conservative thought:

The aide said that guys like me were “in what we call the reality-based community,” which he defined as people who “believe that solutions emerge from your judicious study of discernible reality.”…“That’s not the way the world really works anymore,” he continued. “We’re an empire now, and when we act, we create our own reality. And while you’re studying that reality—judiciously, as you will—we’ll act again, creating other new realities, which you can study too, and that’s how things will sort out.”

The implication for history is plain: While the liberal reads a progression of events and makes a good-faith effort to interpret and learn from it, the conservative takes a different approach, a more active one, shall we say, that sees “discernible reality” as little more than a tabula rasa for the continuation of the conservative story.

Indeed, the last few years have seen conservative authors strike blows against consensus interpretations of history, grafting on our past a conservative tint. In their telling, Woodrow Wilson was the first fascist, the New Deal exacerbated the Great Depression, and Adolf Hitler was, in fact, a man of the left. There are elisions, too. In the modern conservative mind, Ronald Reagan never raised any taxes, never retreated from the Middle East in the face of aggression, and presided over a shrinking deficit—all the opposite of the truth, of course.

Conservatives also have the infrastructure to make sure these fables are disseminated as widely as possible. Instead of Barack Obama, history professor, we have been subjected to daily lectures from Glenn Beck, “America’s historian laureate,” as historian Greg Grandin despairingly called him. The revisionism of people like Jonah Goldberg and Amity Shlaes—not to mention W. Cleon Skousen, a right-wing writer so extreme William F. Buckley Jr. deemed his work beyond the pale—has found a welcome platform on Beck’s show.

In a piece defending Beck from the “university guild,” Shlaes nailed what Beck provides his audience. Beck “has taken an opportunity to teach” viewers who “want a coherent vision, a competing canon that the regulated airwaves and academy have denied them.” That may well be the secret of Beck’s success: His vision of history, a tangle of febrile conspiracies cobbled together from fringe historians and conspiracy theorists, purports to offer The Answer. All of history, as told by scholars, has been a lie. Here, Beck says every night, is what they have hidden from you.

The rank-and-file have taken The Answer to heart. They are eager students; they are always discovering new things. In living rooms across the country, they take notes while they watch, then go to Amazon.com to buy new books. They march to seminar rooms to be taught by Tea Party organizers, who give them the talking points of the new history. They turn out for school board elections and meetings to get the right kind of history in our children’s textbooks—a history that says the Bill of Rights was inspired by Jesus Christ, that the slave trade was actually the “Atlantic triangular trade,” that Thomas Jefferson and his Enlightenment ways were less important than we’ve been led to believe. In a profile of Beck in The New York Times Magazine by Mark Leibovich, a woman waiting in line to get free tickets to a Beck event at the Kennedy Center yells out, “We hate Woodrow Wilson.” That a president from nearly a century ago has become the object of a tailgate jeer underscores just how deeply the conservative rendition of American history has penetrated the public. And thus do obscure and wrong-headed arguments become the foundation for our political discourse.

Beck and company are filling a void left by progressives. The progressive movement for a long time now has failed to develop “a coherent vision,” as Shlaes said Beck offered. We have grown complacent about our accomplishments. Yes, we may have won the culture war, and the achievements of the New Deal and the Great Society are so monumental that we are tempted to think that they are enduring—that that history is settled. But we forget what conservatives know: that everything can be—is—contested. Think FDR’s status as democracy’s savior is sacrosanct? Think again. Fifty years from now, he may well be a controversial figure, his greatness whispered only among cultists. And if you thought that not even posterity could rescue George W. Bush, those Gallup polls should shatter your smugness.

There are signs that progressives are learning. In January, the History Channel announced that it was canceling a miniseries about the Kennedys produced by Hollywood conservative Joel Surnow after numerous complaints about the distortions and inaccuracies in the script. Liberals and moderates have also expressed increasing alarm about the conservative campaign to rewrite our textbooks. Protests like these show a recognition that history needs to be defended from the depredations of propagandists.

But we need to move beyond playing defense and go on offense. We need to promote a progressive idea of history like the one Senator Obama painted for those students years ago. Progressives in government, media, academia, and the grassroots need to engage the battle over our past, and trumpet our accomplishments and the ethos that binds them. In a recent piece in The Washington Monthly, historian Michael Kazin urged Obama to “appeal to history” in his State of the Union address. “[Y]ou might remind Americans that, from the Civil War to the present, the federal government has played an active part in boosting the economy, promoting technological progress, and providing a social safety net,” Kazin wrote. That exhortation applies to the larger progressive sphere.

Just as important is to tell Americans of a past that we need not repeat. We have failed to remind Americans of the disasters that conservatism has visited on American life. A radical idea underpins conservatism: to stand athwart history and yell “Stop!” And from race to foreign policy to the economy, conservatives have so frequently been on the wrong side of history—which is why they feverishly seek to revise it. Let’s hang those failures around their necks. If we don’t fight for history, progressivism itself will be history.