Race remains a fundamental fault-line in American life. That's why the Trayvon Martin murder trial drew wall-to-wall coverage on cable news and why the jury's decision to acquit George Zimmerman drew outraged cries. And on Friday afternoon, a day before planned nationwide protests, President Obama weighed into the fray with a remarkable, unscripted 17-minute address from the White House briefing room.
But by trying to use the bully pulpit to turn this national paroxysm into what he might call a "teachable moment", President Obama reignited conservative criticisms that he is an advocate for identity politics rather than for national unity. Judge for yourself: "When Trayvon Martin was first shot I said that this could have been my son. Another way of saying that is Trayvon Martin could have been me 35 years ago," the president said. "And when you think about why, in the African-American community at least, there's a lot of pain around what happened here, I think it's important to recognise that the African-American community is looking at this issue through a set of experiences and a history that doesn't go away. "That all contributes, I think, to a sense that if a white male teen was involved in the same kind of scenario... both the outcome and the aftermath might have been different."
Beyond the jury's verdict, the president's last point is the bottom line for many: would Trayvon Martin have been shot dead - and his killer acquitted - if he had been white? On the most basic level, it's hard to believe that a 16-year-old white boy wearing a hoodie in Sanford, Florida, would have been automatically seen as suspect.
But negative assumptions run deep - as Obama noted: "There are very few African-American men in this country who haven't had the experience of being followed when they were shopping in a department store. That includes me." There is a residual discomfort and political cost when President Obama speaks as a member of the African-American community rather than as an entirely colour-blind Commander in Chief.
As usual, he walked a line, pointing out that blacks are disproportionately both the victims and perpetrators of crime. And almost lost in his remarks was the implication that his administration would not press federal charges against George Zimmerman despite the wishes of many in this weekend's protests. But despite the fact that Obama's biography shows a person who has consciously tried to be a bridge between black and white communities all his life - from high school in Hawaii to the Harvard Law Review, to the US Senate and to his 2008 campaign for president - obsessive critics project a cynical malevolence on his rise as a figure of racial reconciliation.
That's why the reaction of some conservative populist media figures on Twitter provided a useful insight into their intertwining politics and psychology. For example, Fox News commentator Todd Starnes messaged: "He is truly trying to tear our country apart." Conservative blogger Dan Riehl declared the president "the first Racist in Chief". Talk radio host and Fox contributor Tammy Bruce tweeted: "So Obama 'could have been' Trayvon 35 yrs ago? I had no idea Obama sucker-punched a watch volunteer & then bashed his head in. Who knew?"
Of course, these reactions do not represent all conservatives. But the overheated impulse to declare President Obama "racist" - perhaps first and most prominently uttered by Glenn Beck when he was on Fox News - is an interesting tick, worthy of some analysis. It is a reflexive form of political judo, pre-empting an anticipated play of the race card by instead calling the first black president "racist", attempting to claim the high ground while cloaked in wilful historical ignorance and protected by the approval of hyper-partisan fellow travellers. It is also a version of blaming the victim. Because the irrational anger, suspicion and disrespect Obama inspires in some critics is not unrelated to his race.
The reality of course is that President Obama is both an African-American and the Commander-in-Chief, and both experiences inform his perspective. The president is right to point out that a sense of historic perspective is necessary to understand the emotions beneath our political debates, and that the original sin of slavery - as well as its complicated legacy - remains our deepest wound. Talking honestly about it is part of the cure, encouraging the empathy to see ourselves in "the other", as part of our never-ending quest to form a more perfect American union.