Editor’s note: This is the final installment of a three-part essay on the government’s use of force. The first two parts were published on Feb. 8, and Feb. 15.

Setting rules for the use of force by law enforcement is harder than establishing the procedures to be used in the questioning of captured terrorists for two reasons. The first is race. The second is that we require police officers to engage with and in some cases physically subdue people who may be violent and armed.

The interaction of these two factors complicates our task in finding a balance between the entirely legitimate safety concerns of police officers and the rights of those being arrested, including a few who inevitably will be innocent. Officer Darren Wilson in the Michael Brown case is an example of the former; Tamir Rice, the 12-year-old killed in Cleveland because he had a toy gun, tragically illustrates the latter.

Ideally, we would carefully screen those we hire to protect us from law-breakers, provide them with the best available training, and establish effective procedures to monitor their performance. We could then decide as a society what levels of force would be appropriate in given situations, and have a high degree of confidence that the discretion inherent in the application of these policies by individual police officers would rarely be abused.

But as in other areas of our national life, this ideal comes up against the reality of our racial problem. I very much disagree with those who argue that we have made little progress in diminishing racism. But the accomplishments of the last 60 years have not succeeded in completely undoing the damage inflicted by 200 years of slavery, and 100 more of officially sanctioned segregation – not just in the South.

Racial prejudice is still powerful in its own right, and it is reinforced by the continuing disparities in socioeconomic status.

Police officers are not more affected by racism than the rest of us. But the nature of their work – the difficult, challenging, dangerous job that we ask them to do – thrusts them much more than others into the encounters that are exacerbated by it.

One consequence of our racial history is the deep division between the way in which whites and blacks view events. Two recent cases of African-Americans being killed by law enforcement involve very different levels of police culpability.

Whether or not it was necessary for Wilson to kill Michael Brown, it is clear that Brown was the aggressor, physically resisting a lawful order, and that Wilson had reason to fear for his safety. None of this applies in the Staten Island case. Eric Garner presented no threat to the officers who were arresting him, and could obviously have been subdued without being choked.

But public opinion divides on these two situations not based on their factual differences, but on race. In both cases blacks sharply criticize the police while a majority of whites defends them.

There may be another indicator of the racial element in our judgment of these events. No photo I have seen of the New York police turning their backs on Mayor diBlasio shows black officers among them.

I am strongly inclined to believe that even among police officers understandably traumatized by the murder of two of their colleagues, racial differences affected the degree to which they sought to demonize the mayor for noting that African Americans believe that law enforcement is not even-handed.

Some of the denunciation of the police has been much too harsh and too sweeping, with too little recognition of the perils of their work. I also believe that some police officers and their defenders err grievously in denying that there is any reason for concern.

The outrageous accusation by New York Police Union President Patrick Lynch that the mayor has blood on his hands is as irresponsibly inflammatory as any comment made by the most radical police critic. The attitude he expresses is one major obstacle to the remedial action we should take to resolve the dilemma of race-based beliefs.

The necessary first step is the explicit rejection of both sets of extremes: those who ignore the clear evidence of racial discrimination in the enforcement of the laws in our society, and those who reflexively denounce virtually every case in which police officers use force.

Attitudes matter, and leaders both in law enforcement and in minority communities should use all of their influence with those with whom they have credibility to urge responsible behavior, including the role of self-restraint on fraught occasions. Ironically, it was Mayor Bill de Blasio’s noting that he has tried to convey this message to young African American men that apparently triggered the most vehement response from many police officers.

Secondly, the continuing to keep and enforce laws criminalizing behavior that is not harmful to others and about which society is ambivalent is an invitation to racial unfairness. I know of no claim that the laws against robbery, violent assault or murder are unfairly applied. But the unchallenged statistic that 80 percent of the arrests in New York for marijuana are of racial minorities is one more argument for recognizing that prohibition here works no better than it did with alcohol.

Finally, police forces must understand that they exacerbate the problem by their resistance to noncriminal mechanisms that hold officers accountable for the excessive use of force. The unrelenting hostility on the part of the police rank and file toward fellow officers whose job it is to uncover misbehavior is deeply troubling. So is the fact that law enforcement personnel and their political allies have been very successful in blocking the creation of effective administrative agencies to review their actions.

There are a few cases where criminal sanctions are appropriate against grievous, deliberate police misconduct – for example the sodomizing of Abner Louima years ago in New York. But in most cases the problem is not one of officers committing premeditated unduly violent acts, but of their responding too forcefully in the course of apprehending people who are either physically resisting them, or presenting a potential threat. In these instances, the choice between criminal conviction and no penalty at all is one to which there is no good answer.

Police officers should recognize that it is in their interest as much as the rest of society to collaborate in establishing ways – outside the justice system – to reconcile their right to be treated fairly with the right of people, especially in minority communities, to have their complaints against individual officers fairly adjudicated.

Barney Frank is a retired congressman and the author of landmark legislation. He divides his time between Maine and Massachusetts. Follow him on:

Twitter: @BarneyFrank