CHICAGO » Ralph Medley, a retired professor of philosophy and English who is black, remembers the day when he was arrested on his own property — a rental building here in Hyde Park where he was doing some repair work for tenants.

A concerned neighbor called the police to report a suspicious character. And that was not the first time Medley said he had been wrongly apprehended. A call Medley placed to 911 several years ago about a burglary resulted with the police showing up to frisk him.

“;But I'm the one who called you!”; he said he remembers pleading with the officers.

Like countless blacks around the country, Medley was revisiting his encounters with the police as a national discussion about race and law enforcement unfolded after the arrest of Henry Louis Gates Jr., Harvard's prominent scholar of African-American history. Gates was arrested for disorderly conduct last Thursday at his home in Cambridge, Mass., while the police investigated a report of a possible break-in there. The charge was later dropped, and the Cambridge Police Department said the incident was “;regrettable and unfortunate.”;

In interviews here and in Atlanta, in Web postings and on television talk shows, blacks and others said that what happened to Gates is a common, if unacknowledged, reality for many people of color. They also said that beyond race, the ego of the police officer probably played a role.

But more deeply, many said that the incident was a disappointing reminder that for all the racial progress the country seemed to have made with the election of President Barack Obama, very little has changed in the everyday lives of most people in terms of race relations.

“;No matter how much education you have as a person of color, you still can't escape institutional racism,”; said Keith E. Horton, a sports and entertainment lawyer in Chicago who is black. “;That's what the issue is to me.”;

To be sure, people have found fault with Gates' handling of himself in regard to the arresting police officer, Sgt. James Crowley, who said he was simply fulfilling his duty in investigating the report of a burglary in progress.

The police and Gates offered differing accounts of what happened after officers arrived. By the police account, Gates initially refused to show identification, and as to why the police were investigating, he yelled, “;Why, because I'm a black man in America?

Gates said that he had shown photo identification to Crowley but that the sergeant had appeared not to believe that he lived there. He also said that he did bring up race during the confrontation but that he was not disorderly. According to many comments posted online, Gates, 58, made a tricky situation worse by not easily cooperating. Even a number of blacks acknowledged that he did not help himself by refusing to show deference to a police officer.

“;It is unwise for anyone of any race to raise their voice to a law enforcement officer,”; said Al Vivian, a diversity consultant in Atlanta who is black. “;But the result at the end of the day is this was a man who violated no law, was in his own house, who is the top academic star at the top academic school in the nation, and he was still taken away and arrested.”;

At a news conference on Wednesday night, Obama said he thought the Cambridge police had “;acted stupidly”; in the arrest of Gates.

“;I think it's worse than stupid,”; said Medley, 65, the retired Chicago professor. “;I think it was mean-spirited and ill-intended.”;

Given his experiences, Medley has deeply personal reasons for sympathizing with Gates. But, in interviews, blacks and whites of various ages and experiences with law enforcement showed a tendency to give a benefit of the doubt to Gates over the police in their sharply differing accounts of what happened.

“;It seems to me that Dr. Gates was simply arrested for being upset, and he was arrested for being upset because he's a black man,”; said Wayne Martin, 25, a manager at the Atlanta Housing Authority, who is also black.

The way Martin described himself, he could be the very definition of a “;post-racial”; American. “;I have children I'm trying to raise not to see race,”; he said. “;I'm beyond the whole black-white thing. It doesn't matter to me.”;

Yet Martin could not think of any other way to explain what happened to Gates than racism. He is fascinated by the story. He talks about it at work, to friends, on the phone, on Facebook. On Wednesday, he changed his Facebook status to: “;Wayne Martin is wondering when it became illegal to be angry at a law enforcement official.”;

Martin said that he was heartened to see Obama — who said he is a friend of Gates — address the issue, and that while he agrees with Obama's interpretation of the incident, he thinks the word “;stupidly”; was poorly chosen.

“;That choice of the word was something that I don't agree with,”; Martin said. “;To use such a common offensive term, it almost lowers him down to the level of the folks he's wagging his finger at.”;

Sabine Charles, 37, a white cardiologist who lives in Hyde Park, is married to a black man and said that she could not count how many times people had interrupted the two over the years to ask her, quietly, “;Is this man bothering you?”;

“;I say, 'Guess what? He's not! We're actually on a romantic date, can't you tell?'”; she said. “;Even here in this diverse area I've heard people say, 'Look at those black guys coming toward us.' I say, 'Yes, but they're wearing lacrosse shorts and Calvin Klein jeans. They're probably the kids of the professor down the street.'”;

“;You have to be able to discern differences between people,”; she said, criticizing the practice of racial profiling. “;It's very frustrating.”;

Vivian, the diversity trainer in Atlanta, said that what happened to Gates is “;age old”; in America, but that what is different this time is that it happened in what is supposed to be the so-called post-racial America.

Vivian, 47, said that he had been unfairly stopped by the police in the past, but that he lives by “;an unwritten code”; for dealing with these incidents. “;And Dr. Gates certainly did not obey the code,”; he said.

Quiet politeness is rule No. 1 in surviving an incident of racial profiling, he said. So is the frequent use of the word, “;sir.”;

“;People used to say, 'Look, there's a Colin Powell. There's an Oprah Winfrey.' Now they say, 'There's a black president.' I say, I'm happy to see the exceptions. There's always an exception. But I'm interested in how society treats the average person.”;

That there is a well-known code of behavior familiar to most minorities who are stopped by the police, Vivian said, is testament enough of a problem.

“;It clearly says that we have a lot of work to do,”; he said.