What policies might you institute in order to guide your officers

Consider the following scenario: You are the Chief of Police of a 100 person department that is responsible for a city with a population of 56,000 people. The city has a Muslim population of 3%. The city also has a Latino population of 7%. The Latino population is comprised of 1st generation immigrants as well as U.S. born citizens. The population also includes an undetermined number of illegal immigrants who are employed primarily in the restaurant and landscaping industries. 

The city has passed a local ordinance that states the following: “Any employee of this city, including the police, shall be prohibited from enforcing or assisting in the enforcement of any aspect of The Patriot Act or Federal Immigration Law that may violate the civil rights of any resident of this City.”

As Chief of Police, how do you reconcile the law with your duty to enforce all laws and ordinances? What about the potential necessity of your officers to help federal law enforcement in emergency situations in which they are enforcing a law as defined in the ordinance? What policies might you institute in order to guide your officers?