Mr. Clarence Dupnik, sheriff of Pima County, Arizona, considers Arizona's new immigration law to be unconstitutional and unnecessary:

I have spent over 50 years in the law-enforcement profession in the Tucson community, the past 30 of which I have served as sheriff. ... I have argued from the moment that this bill was signed that it is unnecessary, that it is a travesty, and most significantly, that it is unconstitutional.

...

The more fundamental problem with the law is its vague language. It requires law enforcement officials to demand papers from an individual when they have a "reasonable suspicion" that he is an illegal immigrant. The Preamble to the Declaration of Independence states that "all men are created equal" and that "they are endowed . . . with certain inalienable rights" including "Life, Liberty and the pursuit of Happiness." Those who look "suspiciously" like illegal immigrants will find their liberty in severe jeopardy and their pursuit of happiness disrupted—even if they are citizens or have lived, worked, paid taxes, and maybe even have served in our Armed Forces for decades.

When used in a law-enforcement context, "reasonable suspicion" is always understood to be subjective, but it must be capable of being articulated. In the case of identifying illegal immigrants, the ambiguity of what this "crime" looks like risks including an individual's appearance, which would seem to violate the Constitution's equal protection clause. Such ambiguity is especially dangerous when prescribed to an issue as fraught with emotion as that of illegal immigration.

I have an enormous amount of respect for the men and women of my department—the deputy sheriffs who respond to calls for assistance throughout Pima County every day of the week. I have no doubt that they make intelligent, compassionate and reasonable decisions countless times throughout their shifts. But no one can tell them what an illegal immigrant looks like and when it is ok to begin questioning a person along those lines. This law puts them in a no-win situation: They will be forced to offend and anger someone who is perhaps a citizen or here legally when they ask to see his papers—or be accused of nonfeasance because they do not.

There is a horrible problem with illegal immigration in this country, and it affects the citizens of Pima County every single day. Because of our proximity to the border, our county population demographic is heavily Hispanic (both legal and illegal). That means we must interact with witnesses and victims of crime in their times of need, regardless of their immigration status. Though this legislation states that inquiry into a person's immigration status is not required if it will hinder an investigation, that's not enough to quell the very real fears of the immigrant community.

Law enforcement did not ask for and does not need this new tool. What we do need is assistance from the federal government in the form of effective strategies to secure the border. Additionally, the federal government must take up this issue in the form of comprehensive immigration reform policy. If any good is to come from this firestorm, it is that our legislators will finally recognize that a problem exists and that they are the only ones with the authority to address it.

Arizona's Immigration Mistake [Wall Street Journal]