You may have noticed a pattern in American politics. Whenever conservatives have no answer to pressing social and economic issues, they change the subject, usually by attacking opponents in such a way as to draw our attention from those pressing issues. It happened to Martin Luther King Jr., and, absurdly, it is still happening. Every year on the February day commemorating the life and legacy of the civil-rights hero, white nationalists come out of the woodwork to calumniate his memory by claiming that he was a drinker, philanderer and plagiarist.

White nationalism continues to influence mainstream views of President Barack Obama. He can't be a legitimate president, because he wasn't born in the US (false). He won the presidency, because he was black (ha!). He isn't American, because he was born a Muslim (huh?). He's weak (um, cf. Osama bin Laden). He isn't smart because he needs a Teleprompter (ugh). And the most ridiculous of all: He's a socialist (Oh yeah; the fact that he's done more to shrink the federal government than Republican Presidents Reagan, Bush I and Bush II defines socialism!).

We saw something similar happen to Elizabeth Warren last week. She is the Democratic rival of US Senator Scott Brown, the Massachusetts Republican who won a special election in 2010 after Edward Kennedy died. Warren rose to become a candidate after working with the Obama administration on financial reform legislation (known as Dodd-Frank) and on the creation of a federal agency to protect consumers against Wall Street chicanery. As a result, Warren has become a folk hero of sorts, especially to those sympathetic to the Occupy Movement, because of her plain-spoken way of talking about money, power and how they distort American ideals. She may be best known for a viral video in which she explains why asking the rich to pay their fair share is not class warfare but instead part of the social contract:

There is nobody in this country who got rich on his own. ... You moved your goods to market on the roads the rest of us paid for. You hired workers the rest of us paid to educate. You were safe in your factory because of police forces and fire forces that the rest of us paid for. ... Part of the underlying social contract is, you take a hunk of that [wealth] and pay forward for the next kid who comes along.

Yet for the last month, Warren has been dogged by questions about her Native American lineage. At issue: Why did Harvard University, where she has been a professor of law since the mid-1990s, list her as a minority when the New England Historic Genealogical Society has no evidence that she is or is not descended from a Cherokee ancestor? The implication on the right is that Warren lied about being a minority to advance her career, thus discrediting and casting a pall of doubt over the economic populism.

Warren believes she is part Cherokee because her family told her she was. On Wednesday, she told the Boston Globe: "My mother and my grandparents and my aunts and uncles often talked about our family's Native American heritage." Yet her explanations raised suspicions. She said she didn't know Harvard identified her as a minority until a reporter told her. Later on, she said she'd discussed her ancestry with Harvard after being hired. That apparent discrepancy was enough to fuel one of two suspicions: 1) that she is political novice unprepared to run with the big dogs or 2) that she is an opportunist using affirmation-action laws to get ahead, thus mocking the ideal of equal opportunity that she says all Americans deserve.

But, as Timothy Noah points out, this is a canard. Warren denies that her minority status had anything to do with her hiring and Harvard Law confirms this. Even if she had benefitted from affirmative action, it wouldn't have been because she is Native American. It would have been because she's a woman. At the time of her appointment, almost all faculty at Harvard Law were men, and its priorities, in terms of race, were to hire African Americans. And besides, Noah writes, Warren wasn't covering up anything. She just didn't remember what she said: "You ask me what I ate for breakfast. I say I don’t remember. You point out that I have a stain on my tie that looks like fried egg. Oh, right, I say. I had a fried egg. Is that 'coming clean'?"

Even so, this appeared to ding her credibility. To her conservative and Republican adversaries, she is the affirmative-action candidate just as Obama is the affirmative-action president, which according to the absurd logic of white nationalism means that neither had to earn success. Instead, it was given to them.

Perhaps bigotry like this inspired a writer for the National Review, a conservative magazine, to dash headlong into accusations that Warren is a plagiarist (recall that MLK got the same treatment). The writer charged that a book Warren had co-authored, All Your Worth: The Ultimate Money Lifetime Plan, was copied from Getting on the Money Track by Rob Black. Some passages are identical, but, as Alex Pareene of Salon wrote, Warren didn't plagiarize Black. Black plagiarized Warren. His book came out months after hers.

You'd think with all this whipped up worry about Warren's credibility that Massachusetts Democrats might have reconsidered their support for Warren during the Democratic Convention on Saturday. And you'd think that Warren might have toned down her message of economic populism. But you'd be wrong.

In a speech that night, she blasted Brown, and called into question his reputation as a moderate. "Whoever he once was, I can tell you who he is now," she said. "Scott Brown is a Wall Street Republican. A big oil Republican. A Mitt Romney Republican."

That's why Republicans are worried. Not only is Warren an expert in financial law; not only does she express herself in populist tones; her rise comes as Americans are unsatisfied with talking about "opportunity." Instead, they want to talk about "fairness." The American Dream is powerful, perhaps doubly so in reverse. If people feel the game is rigged, they get mad, and when they get mad, watch out.

With the delegates tallied, it was official: Warren had won the most delegates in Massachusetts history, with almost 96 per cent of the vote. The margin of victory was so wide it obviated the need for a primary, and it seemed to put to rest the counterfeit controversy over her Cherokee ethnicity. A new Globe polls shows Warren in a dead heat with Brown, with 72 per cent saying that the Cherokee thing is over.

Not so for Brown.

After the Democratic delegates were counted Saturday, he told reporters that he expects questions of Warren's ancestry to continue due to her "patterns" of lacking credibility. But that's not the pattern we should be watching for. Instead, what we'll see is Brown bringing up Warren's background any time he doesn't want to talk about economic justice. As conservatives have since the time of Martin Luther King Jr. and beyond, he will attack in ways that draw our attention away from what's truly important.