In 1972, Edmund Muskie, a liberal Senator from Maine and the front-runner for the Democratic nomination, sparked headlines when he said he couldn’t consider Los Angeles Mayor Tom Bradley for vice president because the country wasn’t ready for a “black” in the White House. The squall passed because it was understood that Muskie had only blundered into speaking the impolitic truth.

A similar truth had been spoken among Democratic Party leaders in 1960. Old enough to recall the bigotry-soaked rejection of Catholic Al Smith's presidential bid a generation before, they worried that John F. Kennedy, another Catholic, would fail the same religious test. Kennedy eked out a first-run ballot victory at the Democratic Convention because he had swept the primary contests, leaving the party with a stark choice between acceding to his nomination or alienating Catholics wholesale — an even more certain road to defeat.

The tactics of stoking racial resentment are well-known, even by the media that pretend not to notice them.

We dared to hope that Obama’s election marked a new day in America; we’ve been learning, against our wishes and our will, what we always should have known: Racism is far harder to overcome than religious bias. Indeed, it’s the highest hurdle because its evil is still woven deeply into the fabric of popular reflex and fear.

America is a work in progress, and the circle of tolerance, followed by equality, constantly widens. Kennedy’s election did push out the frontiers of freedom. Undeniably, and more profoundly, Obama’s did too. The country, if not all of it, swelled with pride to see him take the Oval Office. But old bigotry assumes new guises.

There is no room or reason — except on Fox News — to doubt the racist impulses that flourish in the precincts of the Tea Party, amplified by fellow travelers in talk radio and the GOP. Republican Senate Leader Mitch McConnell and most of his colleagues tremble at the notion of criticizing Limbaugh, Hannity, and Beck’s commercial traffic in racial resentment. They see profit in prejudice, danger in rebuking it. The moral bankruptcy of the Republican Party, which returned to power 40 years ago with a vengeance called the “Southern strategy,” has been extended and deepened. Then, the source of grievance was an African-American seated at the lunch counter. Now it is an African-American seated in the Oval Office.

The tactics are well-known, even by the cowardly media that pretend not to notice them. Accuse the advocates of affirmative action of being racist because they favor “quotas”—even though they don’t. Smear Supreme Court nominee Sonia Sotomayor as racist because she spoke, truthfully, of the distinctive perspective a Latina woman would bring to the bench. Use Fox News to elevate obscure, hapless black radicals into a clear and present danger. And in the latest incarnation — spawned by Andrew Breitbart, the right-wing propagandist who helped destroy Acorn with fraudulent, selectively-edited tapes — flack a similarly bogus tape to falsely convict Shirley Sherrod, an Obama administration Agriculture Department official in Georgia, of bias against a white farmer.

Breitbart, like Limbaugh and Fox News, home base for racial propaganda, has no shame.

But that only made it more painful to observe the panic of those in the Obama administration who, without pausing to check the facts, rushed Shirley Sherrod to the stake. Why in the world, given the tainted source of the video, would they believe the charges? The answer is plain: The far-right strategy of tagging advocates of equality as “racist” has succeeded in intimidating too many of them.

In a staff meeting Tuesday, a top White House aide reportedly praised the West Wing operation for pushing Agriculture Secretary Tom Vilsack to dispose of Sherrod. By the end of the day, as the truth emerged, the White House spin shifted — the firing was all Vilsack’s fault. But according to Sherrod herself, a department official told her “the White House wants you to resign.”

The debacle was, White House spokesman Robert Gibbs said, “a teachable moment.” More aptly, it was a pathetic spectacle, redeemed at the end only by Vilsack’s genuine humility and willingness to take responsibility — which wasn’t his in the first place.

Breitbart pulled off his defamatory fraud fully aware of the reality that uniquely challenges this president: Race was the third rail of Obama’s 2008 campaign, requiring him to be the least angry black man in America. As president, he saw the media flip into a frenzy when he commented, accurately, that the Cambridge police had reacted “stupidly” in a confrontation with Harvard professor Henry Louis Gates, an African-American who was detained for breaking into his own home.

This week, the president watched the Sherrod episode grab the spotlight from the passage of historic Wall Street reform and the extension of unemployment benefits — the two stories he wanted on television and in the headlines.

But racial controversy always commands the news, even more so with Barack Obama in the White House. That’s why the White House dismisses evidence that opposition to him is race-tinged; the reaction, if Obama acknowledged the obvious, would be predictable and powerful. Thus Vice President Biden, appearing on the Sunday talk circuit, was careful to aver that the Tea Party is not a “racist organization” — which may be a technical truth but elides the fact that the movement is powered in part by racial animus and stereotype.

To insulate Obama from racial misgivings, the White House doesn’t want race to become an issue — ever. That’s understandable. But at stake now is the character of the country and the Obama presidency. It was morally wrong to discard Shirley Sherrod to blunt the vituperation of Breitbart and racial opportunists. It’s a political mistake to assume the racial opportunists can be deflected or appeased. They must be defied — and so must the race-coders who traffic in gentler but no less insidious poisons. The Birthers, the madrassa mongers, the furies who demand to “take our country back” are proxies for prejudice. (Take the country back from whom? From the oldest political party in America?)

At a very difficult time in our economy, this president also represents the chance — and sadly to some, the threat — that we will finally, largely, overcome the ugliest wound in the long span of our national life. Obama doesn’t have to focus on race; admittedly, he can’t afford to. But he can’t let those around him buckle in the face of appeals to what was, and is, worst in America. At every point, Obama must stand for our best hopes and our better natures — which is what put him in the presidency in the first place.