Imagine yourself a hard-working, law-abiding, young black man in any big city in America. You hail cabs, and they speed by as though you were invisible, only to pick up a white person down the block. You call to order a pizza, only to have the delivery driver refuse to come to your door or never show up at all. You go out to buy yourself a pizza, only to get pulled over for "driving while black" or stopped and frisked for walking while black. Such outrages are a constant theme of your daily life.

But at whom should you be outraged? At the cabbies-most of whom, in cities such as Washington, are themselves black-for guessing that a white guy or an old black woman is less likely to rob or kill them than a guy who looks like you? At the delivery drivers, for calculating that they are more likely to become crime victims on your street than in some lily-white suburb? At the cops, for wagering that they will find more illegal drugs and guns by stopping young black men than, say, people who look like Rosie O’Donnell or Bill Gates or Bill Cosby?

The cabbies, delivery drivers, and cops are all using racial stereotypes in ways that aggravate our legacy of racial oppression and inequality. So should all forms of racial profiling be illegal? Should cabbies, delivery drivers, and cops be condemned or penalized for treating white people and African-Americans differently? Should their employers be held liable in discrimination lawsuits, such as the one filed by a civil rights group on June 7 against Diamond Cab Co. of D.C., based on evidence suggesting that Diamond cabs almost always show up when the dispatcher is called from affluent white neighborhoods and almost never show up when the call is from a black neighborhood? These are complex questions, and too often they are answered in simplistic terms.

Consider the approach of New York City Mayor Rudolph W. Giuliani. He presides over a police department that for years has been plausibly accused of using racial profiling to stop and search young black men in ways that often seem close to harassment. Yet last year, he launched a big crackdown on other suspected profilers by immediately seizing the licenses and cabs of drivers who refused to pick up black undercover officers posing as would-be passengers or to go to black neighborhoods. Giuliani’s approach seems backwards. So do the laws and court decisions around the country that make it illegal (at least presumptively) for cabbies to consider race when guessing whether a potential passenger might be dangerous, while at the same time allowing cops to do so when deciding whom to stop as a possible drug courier.

Steven A. Holmes of The New York Times wrote last year about his anger at being stopped by a cop in his own mostly white Washington, D.C., neighborhood for no apparent reason except his black skin. Then Holmes posed a thoughtful question: "Hadn’t I done the same thing myself?" While driving a cab at night as a college student in New York City, Holmes recalled, he had used "my own form of racial profiling" after being robbed twice by young black men. "My sense of tolerance and racial solidarity was tested every time a casually dressed young black man, especially one in sneakers, tried to hail my cab," wrote Holmes. "Most times, I drove right by. I sometimes wondered about their reaction, but I kept thinking that if I guessed wrong, I could pay for my mistake with my life."

Holmes’ experiences as both racial profilee and racial profiler reinforce my sense that cabbies and delivery drivers who resort to race-based (and attire-based) stereotypes to increase their odds of staying alive deserve our sympathy, if not our approval. Law enforcement agencies that do so to increase their odds of finding illegal drugs or guns deserve neither.

The point is not that it’s necessarily racist, or even unreasonable, for cops, cabbies, or anyone else to associate young black men and poor black neighborhoods with danger. "Statistics abundantly confirm," as Harvard law professor Randall Kennedy noted in The New Republic last year, "that African-Americans-and particularly young black men-commit a dramatically disproportionate share of street crime in the United States. This is a sociological fact, not a figment of the media’s (or the police’s) racist imagination." Nor was it racism that prompted Jesse Jackson (in 1993) to say: `’There is nothing more painful to me at this stage in my life than to walk down the street and hear footsteps and start thinking about robbery-then look around and see somebody white and feel relieved."

Nevertheless, racial profiling by police should be held to be unconstitutional, as Kennedy asserts, even when there is a statistically valid basis for believing that it will help catch more drug dealers or illegal immigrants. That kind of racial profiling is rarely justified by any concern for the officers’ own safety, and it is often hard to distinguish from plain old racist harassment. The negative impact of such profiling is far-reaching: It involves the discriminatory use of coercive government power against people who already experience discrimination at every stage of the criminal justice process; it subjects thousands of innocent people to the kind of inconvenience and humiliation that most of us associate with police states; and it makes law enforcement more difficult by fomenting fear and distrust among potential witnesses and jurors. These costs far outweigh any law enforcement benefits.

Cabbies, on the other hand, who are hailed by thousands of people every year, have much more at stake than arrest statistics and are almost uniquely vulnerable. They are obliged to take passengers wherever they want to go and are virtually defenseless when passengers sitting behind them pull guns. Cabbies must decide whether would-be passengers look safe enough based on little more than skin color, gender, age, and attire. Theirs is one of the most dangerous jobs in the country-more dangerous in terms of homicide rates than being a police officer.

"Late at night, if I saw young black men dressed in a slovenly way, I wouldn’t pick them up, either," Sandra Seegars, a D.C. taxi commissioner and longtime community activist, said earlier this year. This touched off a round of pious denunciations, as though (Washington Post reporter Megan Rosenfeld observed) "the body politic [had] … stuck its collective finger into a light socket." The Post itself complained in an editorial that Seegars "would approve of discrimination against an entire segment of passengers based solely on race and appearance." But Seegars won praise from cabbies, including many who are (like her) African-American.

It is not racism that motivates most cabbies and delivery drivers when they deny equal service to black customers. Their main motive is self-preservation. One can fault them for giving undue weight to racial stereotypes in their calculus of risk. But how would you feel about having your own calculus of personal risk second-guessed by mayors, bureaucrats, judges, jurors, and editorialists?

This is not to deny that we should make every effort to minimize refusals by cab drivers and others to serve black people (or black neighborhoods) on an equal basis. Our laws should crack down on the use of race alone as a basis for denying equal service to anyone. And we should be willing to bear significant social costs to promote equal service. Retailers, for example, should be barred from having their security guards tail black customers based on the assumption that they are statistically more likely than others to be shoplifters. Even assuming that this practice might cut down on shoplifting, that’s not a good enough reason to justify the insult to the vast majority of black customers who are not shoplifters.

The law should also push taxicab companies, pizza chains, other employers, and governments to give drivers and other employees every possible incentive, including better protection, to provide equal service. Much can be done along these lines: The D.C. Taxicab Commission, for example, plans to require that cabs be equipped with bulletproof partitions between front and back seats or with security cameras. And Domino’s Pizza agreed, on June 5, with the Justice Department to use methods more precise and reliable than racial stereotyping to identify neighborhoods deemed unsafe for delivery drivers.

But we should also have a decent respect for the intuitions of people with dangerous jobs on how best to protect themselves. Such people, as Kennedy wrote in a 1997 book, "like everyone, are caught up in a large tragedy that will require more than individual good will and bravery to resolve."