The Supreme Court has given police officers a license to lie. Previously, the Court ruled that when officers lie at a criminal trial, presumably to obtain a conviction, they are immune from civil suits. On April 2, 2012, the Court decided Rehberg v. Paulk, finding that all witnesses, including police officers, who lie before a grand jury in order to obtain an indictment are also immune from civil lawsuits. According to the Court, there is no reason to hold officers civilly liable since they are subject to criminal prosecution for perjury. However, this is actually a license to lie because a perjury charge would have to be brought by the prosecutor— the same prosecutor who called on the officer to testify.

Perjury prosecutions of police officers for lying before a grand jury simply will not happen because officers and prosecutors have an interdependent relationship.