In Endres v. Indiana State Police, 334 F.3d 618 (7th Cir. 2003), the court reviewed several prior decisions involving law enforcement officers and held:

   Law-enforcement agencies need the cooperation of all members. Even if it proves possible to swap assignments on one occasion, another may arise when personnel are not available to cover for selective objectors, or when (as in Hardison) seniority systems or limits on overtime curtail the options for shuffling personnel. Beyond all of this is the need to hold police officers to their promise to enforce the law without favoritism -- as judges take an oath to enforce all laws, without regard to their (or the litigants') social, political, or religious beliefs. Firefighters must extinguish all fires, even those in places of worship that the firefighter regards as heretical. Just so with police.

In Rodriguez v. City of Chicago, 156 F.3d 771 (7th Cir. 1998), the court found that a Catholic police officer who did not wish to work outside an abortion clinic could exercise his right to transfer to another district under the collective bargaining agreement -- and that ability to transfer constitutes a reasonable accommodation. In a concurring opinion, Chief Judge Posner argued that the majority should have based its opinion on the ground that a police officer cannot refuse to defend the citizenry just because his beliefs differ from those he is assigned to protect. In other words, any accommodation would constitute an undue hardship.