Just a year ago, we had what President Obama called a “teachable moment” in race relations. That was in the wake of the arrest of Henry Louis (Skip) Gates Jr., a well known Vineyard summer resident.

You remember it, of course. Professor Gates, probably the nation’s foremost black academic, was arrested in his own home after Cambridge police responded to a suspected break-in.

There was no just cause for his arrest, although there was some provocation of the “you don’t know who you’re messing with” variety from Mr. Gates. Then the President said the police had acted “stupidly,” then there was a firestorm of criticism from the political right about his comment, and then an attempt to quench all of it with the famous beer summit involving Mr. Gates, Sergeant James Crowley, the President and Vice President.

Twelve months later, what has been learned from that teachable moment?

Well, in the case of the Obama administration, it appears the lesson was that it should not allow itself to be outflanked by the punditocracy, but rush to its own presumption of guilt.

A year on from Skip Gates’ arrest, the administration rushed to sack Shirley Sherrod, without considering any evidence beyond a deliberately-misleading snippet of a speech she made, presented by a right-wing blogger. A black woman whose life story preaches racial reconciliation was accused of racism and lost her job.

And that was utterly shameful, says Charles Ogletree, Harvard law professor, counsel to Skip Gates and recent author of the book The Presumption of Guilt.

But maybe, he said hopefully on Tuesday, sitting in the living room of his Oak Bluffs summer home, it also was another teachable moment.

And the first thing the Gates and Sherrod incidents teach, he said, is that “Race is perhaps even more of a lightning rod than it was before Obama’s election.”

As his book records, the racial divide in the reaction to President Obama’s comment that the police acted stupidly was wide. A CNN poll asking whether the president had acted stupidly in criticizing them found 63 per cent of whites thought he had, while only 26 per cent of blacks did. Also, 61 per cent of blacks sympathized with professor Gates, compared with 29 per cent of whites.

The Gates incident, Professor Ogletree said, “blackened Obama in some ways.

“A lot of people took offense at his comment about the Cambridge police acting stupidly.

“On the other hand African-Americans applauded the fact that for the first time in their lives, a President of the United States said we have a problem with racial profiling in America.

“That was a pretty profound statement. It opened up doors for a dialogue we hadn’t been having,” he said.

The cynic might say there had been less dialogue than shouting since then, as conservatives charge racism on the part of blacks, including the President, and liberals charge racism on the part of whites, including the tea party supporters.

This cynic suggested that maybe in the wake of the beating the President took over the Gates incident and the heat of the dialogue since, the Obama administration is timid and reactive on the subject of race.

“Absolutely,” Professor Ogletree said.

That was apparent in the President’s comments after he rang Ms. Sherrod to apologize, in which he said the dialogue could not be driven by the 24-hour news cycle.

“It wasn’t the President [who was responsible for sacking her], but people connected with the White House who obviously thought, we’ve got to root out discrimination, whether it’s by blacks or whites or anyone else,” he said. He continued:

“I think that a laudable goal, but knowing the relevant facts and taking the time to gather information is important.

“What happened to her is shameful in that no one did a full investigation of the background or her incredible story in an effort to promote racial harmony.

“I think the good news is that now she is a national figure. She is adored by those who know more about her. I’m hoping that she will be able to use this as a way she can go and talk about the things that she’s learned.

“Her father was murdered by a white farmer. Her husband was one of the founders of SNCC [the Student Nonviolent Coordinating Committee]. She spent the formative years of her career promoting opportunities for all farmers in the South.

“Her family is well regarded throughout the South. A lot of people know the Sherrods for what they’ve done over the last four or five decades. You’d think that somebody would have been aware of her record . . .”

In fact, the real message of Shirley Sherrod’s shamefully misrepresented speech was about class, not race. It was that poor people needed help regardless of whether they were black or white.

Which brings us, in a roundabout way, to the subject of Professor Ogletree’s book. For it also is about the intersection of race and class.

No doubt race was the major factor in precipitating the Gates arrest. A black man was seen apparently forcing his way into a house in Cambridge. The presumption was that he did not belong there.

But it was class which escalated the dispute.

Said Mr. Ogletree: “What Professor Gates had to say was a lot about class: ‘Do you know who I am, who you’re messing with?’ The race was less significant than, ‘Everybody knows me. I’m not the kid from West Virginia who grew up in segregation; I’m a graduate of Yale with a PhD. I’ve received a MacArthur genius scholarship, written a dozen books, been on PBS.’

“That was all about class.”

Then, when President Obama came to Mr. Gates’s defense, he said: “People saw this President and this Harvard teaching professor challenging this working class Cambridge police officer. It was class again.”

His book cites other examples, such as the one about the black teenager who was repeatedly stopped by police when on his way to visit a friend on a street which was home to some of Cambridge’s most prominent residents. Eventually the owner of the house he was visiting, law professor Alan Dershowitz, took him down to the police department, introduced him to the officers, and gave them a photograph, in the hope that he would not be bothered in future.

But Professor Ogletree is bothered by the suggestion that certain African-American people should get a such a pass.

“I don’t want a special privilege because of prominence,” he said.

“That’s why the class issue is woven throughout this narrative. If Jamal Smith had been arrested on his porch on July 16, 2009, how much publicity would it have received? Zero.

But it was Skip Gates. It wasn’t because he was black; it was because he was someone, that it became an issue.”

And so the second half of his book sets out to push that issue by citing 100 cases of prominent black men who have experienced the same kinds of problems that unknown African-Americans — and indeed people of lesser social status of all backgrounds — so frequently face.

“I did that because people would not pay attention to Jamal getting arrested or profiled, or being mistaken for the waiter, or being asked to park somebody’s car, or take their coat to be checked.

“But if you say John Hope Franklin or Vernon Jordan or Spike Lee, or Eric Holder or Justice Thurgood Marshall or Judge Leslie Harris or Judge Reggie Walton or Judge Ricky Roberts, they’ll say ‘Wow, it’s happening to them, too?’

“It shows the problem, that it’s not just happening to people who don’t have the power. It’s happening to everyone,” he said.

And not just black people. A lot of the scenarios presented in the case studies will be familiar to people of other racial backgrounds. The Asian-American in Seattle, the Hispanic in New Mexico, the white guy with long hair, driving an old Volkswagen, anyone who might be treated poorly on the basis of assumptions.

“My point is that Skip Gates has provided the opportunity to talk about these issues. My focus was on Gates, but only as the window to look at the larger problem.

“I’ve had people on this Island tell stories like this. I’m saying, share your stories.”

Nor does he blame the police specifically, although they are the ones most often forced to address it.

“They need proper training, resources,” he said. “I feel very bad for the police in Arizona, who have a untenable position, having to look at somebody, their dress, their accent, and decide who is an undocumented worker and who is a naturalized citizen.”

Mostly, of course, the presumption of guilt attaches to African-Americans.

He referenced one example in the book: that of Robert Wilkins, an African-American lawyer pulled over on the highway in Maryland on the way home from his grandfather’s funeral, for no probable cause, a classic case of “driving while black.”

He eventually won a lawsuit against the state.

“That’s the good news. The bad news we learn eight years later is that 70 to 75 per cent of the people stopped on the Mayland Highways are African-American, even though they only represent 17 per cent of those driving on the highways. That tells you the practice of racial profiling continues,” Mr. Ogletree said.

And creating a class exception for people of achievement only exacerbates the problem.

The aim, he said, is “Because African-Americans of a different class, your Shirley Sherrod, can’t come to Harvard Square, can’t shop in Cambridge, without being profiled.

That’s the divide. I don’t want to create a class exception.”