Crossposted at HuffingtonPost.

For the moment, President Obama and many pundits have arrived at a comfortable middle ground: Professor Henry Louis Gates, Jr. and Sergeant James L. Crowley each over-reacted to the now famous events at the Professor's home. The parties are apparently going to affirm that perspective with a beer at the White House. This is a calming resolution, but it sends the wrong message about the proper role of law enforcement under our Constitution.

Professor Gates is not the first person to complain about the way he was treated by a police officer. Many people have done so in language more graphic and more demonstrative than that of the good professor. The law books are full of cases which provide helpful guidance to law enforcement in these difficult interactions. Notwithstanding the issues of race and class that dominate the public discussion of the Gates matter, these cases involve a broad range of people. Some of the cases involve minorities; some do not. They include people from all walks of life and socio-economic background. Many of the cases arise out of the use of vague "disorderly conduct" laws, as was the case with Professor Gates. Other examples involve the enforcement of very specific prohibitions on the use of a particular category of speech in addressing a police officer, like cursing, or obscene or opprobrious language.

No matter the specifics of the law being enforced, controlling principles have become well established in the courts. First, people, including arrestees, have a right to free speech allowing them to protest their treatment to the arresting officer. According to the Supreme Court, "the First Amendment protects a significant amount of verbal criticism and challenge directed at police officers." To be certain, these rights are not absolute. The speech is not protected if it constitutes a true threat or "fighting words" -- "those personally abusive epithets which, when addressed to the ordinary citizen, are, as a matter of common knowledge, inherently likely to provoke violent reaction." Mere vulgarity and humiliation are not enough.

Of course the notion that the police can legitimately respond with force in the face of epithets seems strangely at odds with the concept of the modern law enforcement professional. The courts agree. As Justice Powell wrote in the seminal case, Lewis v. City of New Orleans, "a properly trained officer may reasonably be expected to exercise a higher degree of restraint than an average citizen, and thus be less likely to respond belligerently to 'fighting words'."

So, what should Sergeant Crowley have done when Professor allegedly complained quite loudly of being profiled and made a reference to Crowley's "mama"? To begin, he should not have felt threatened. After all, Professor Gates is of slight frame, has limited physical mobility and walks with a cane. The sergeant was well advised not only to listen to Justice Powell, but also to heed the age-old parental guidance on the potential injury from "sticks and stones," as compared to words. He was bound to conclude that Gate's words were protected because a properly trained police officer acting reasonably would not lose his cool over these comments and use force against Gates. In short, he should have walked away. Police business was over; it was no time to sulk or avenge the alleged insults.

It also was no time to order the Professor out of his own home where the alleged presence of neighbors and the continued harangue by Gates was supposedly additional grounds for arrest. The decisions of Massachusetts' own state courts simply do not allow arrests for disorderly conduct because a person uses loud, non-inciteful language in the presence of a small number of peaceful individuals who gather at the scene of an arrest. This limitation under state law should have been known to a reasonable police officer.

Everyone knows that as prudent people we ordinarily should not get "lippy" with a police officer, but Professor Gates is not guilty of violating that maxim. He was standing up for his rights. The Constitution protects our right to protest injustice, including on those occasions when we are the victims. Gates was exercising his rights and Crowley violated them.

There is no middle ground.