Institutional racism is still a major force in U.S. society.

We still have many segregated neighborhoods, ranging from gated communities to isolated hill towns. Many white Americans grow up in neighborhoods that are predominantly white, with white police and firefighters, teachers, and clergy, watching the news shaped by white editors working for media outlets with white executives and owners. Whether considering access to quality education or well-paying jobs, whites enjoy greater privilege than most people of color, particularly African Americans.

The criminal justice system discriminates against African Americans at all levels - they are more likely to be stopped, frisked, charged, convicted, incarcerated and sent to prison with longer sentences. Consequently, despite being less than 14 percent of the U.S. population, African Americans are nearly 50 percent of the prison population. And yet many whites think that because we have elected a multiracial black president that we live in a post-racial society. How is this possible?

The recent incident involving Dr. Henry Louis Gates Jr. and the Cambridge Police Department and the controversy over President Obama's remarks is part of a historical pattern of racism and white privilege that has plagued this nation since its inception.

Like the majority of those commenting on this incident, I do not know the details of what actually transpired when Dr. Gates was arrested in his own house by a white policeman. What I have seen, however, is an outpouring of outrage against President Obama's remarks when he used the word "stupidly" to describe the behavior of the police involved in this incident.

This was an unfortunate phrase for a number of reasons. One is that it primed white fears that our post-racism black president was playing "the race card." As president and particularly as the nation's first non-white president, he must calibrate his words very carefully or risk an indignant backlash from whites who do not like to be reminded of their racial privileges. And by implying that this was a stupid act, the outcry in much of the media is focused on the behavior of individuals and the alleged smearing of police officers doing their jobs, rather than the historical and social forces that form the backdrop for a recurring pattern of such encounters.

The United States was founded on what Charles Mills has called a "racial contract," the underside of the social contract so eloquently expressed in the Declaration of Independence and The Constitution. While George Washington, Thomas Jefferson, James Madison and many others were extolling the "rights of man," they were holding African-American slaves. Over a century later and after the Civil War, President Woodrow Wilson re-segregated the federal government. In recent memory, Richard Nixon, Ronald Reagan and George Bush Sr. ran presidential campaigns appealing to white resentment at the expense of African Americans. Many white U.S. presidents have played the "race card."

The use of the police to harass African Americans can be traced back to a time shortly after the Civil War. As Douglas Blackmon has described in his meticulously researched book "Slavery By Another Name," in many southern states white policemen and other law enforcement officials would arrest African Americans for alleged crimes such as swearing, spitting in public, making statements defaming white women, being a public nuisance, vagrancy and other difficult to disprove crimes. The men were often sentenced and fined by compliant white magistrates without any evidence or right to fair hearings.

Unable to pay their fines, they were then leased to mines, industrial corporations such as U.S. Steel, and plantations, where they were shackled, underfed, beaten, abused and forced to work in dangerous and degrading circumstances, where many died or suffered serious illness and injury. These practices lasted until World War II. The racial misuse of the criminal justice system has deep and tortured roots.

The question remains why many white people think that racism is a thing of the past and why so many were more concerned about President Obama's remarks than the arrest of Dr. Gates.

One possible reason is that the threat Dr. Gates faced is not salient for most white people in the United States. I have never been stopped by the police for driving while white. As a white person, the few times that I have been involved with the police, we have engaged in a mutual dance of deference - I expect to be treated politely and fairly and respond in kind. In return I have been treated with dignity and deference and even if I am given a ticket or citation, we usually engage in a de-escalating dance step and both parties walk away feeling respected.

This choreographed ritual is not as available for Dr. Gates and other African-American men dealing with white police officers. The more typical dance that they are invited to participate in is fraught with danger, with the expectation of dominance by the police and subservience by the accused.

Many low-income whites in the U.S. suffer the indignities and injuries of class and often do not feel very privileged. African Americans of all social classes, as the Gates incident reminds us, have to worry about racism, which even poor whites do not encounter.

I have never worried, as many African American men do, about being shot by the police while reaching for my wallet. I have never been called a racial epitaph or beaten by a policeman for being white. I am not asked to show my driver's license when paying by credit card in my community as many of my colleagues of color are.

I can live under the illusion that my social and professional achievements are entirely due to my efforts, not because of unfair racial privilege that gave me greater access to education, jobs and wealth. And perhaps it is the guilt and shame about realizing this, along with the ubiquity of other white people who share this illusion with me, that may make it difficult for me to acknowledge the extent of racism in my own country - because I am never the target of it.

Henry Louis Gates Jr. is a distinguished and accomplished intellectual, teaching at the nation's premier university.

The fact that he, too, is vulnerable to the sting of racism might confirm what many people of color already believe about their vulnerability to police assaults on their privacy, safety and dignity. Those who carry passports of white privilege usually do not share these fears and instead can become angry when the alleged "race card" is played.

In order to understand what happened with this recent situation and to move beyond this dynamic, to truly achieve a "post-racial" society, white people need to ensure that the privileges that we carry, whether we want these racial privileges or not, are shared by all.

Joshua Miller is a professor at the Smith College School for Social Work and co-author, with Ann Marie Garran, of "Racism in the United States: Implications for the helping professions."